JPS5938466B2 - Hydraulic transmission control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention opens and closes a clutch valve provided in a hydraulic closed circuit of a hydraulic transmission to obtain a clutch-on state in which the hydraulic motor is operated and a clutch-off state in which it is inoperative. The present invention relates to a control device configured as described above.

A hydraulic closed circuit is formed between a swash plate type hydraulic pump connected to an input shaft and a swash plate type hydraulic motor connected to an output shaft, and the hydraulic closed circuit includes suction and discharge ports of the hydraulic pump, and a plurality of communication boats of the hydraulic motor. a distribution board that is open at one end surface and rotates together with the motor cylinder of the hydraulic motor;
A high pressure chamber that communicates between the discharge port and the communication port on the high pressure side and a low pressure chamber that communicates between the suction port and the communication boat on the low pressure side are defined on one end surface of the distribution board supported by a fixed shaft. Hydraulic transmissions are already known in the art.

In such a transmission, the present invention has a piston type clutch valve that slides to control communication between the low pressure chamber and the high pressure chamber and a hydraulic servo motor that operates the clutch valve built in the fixed shaft, and a hydraulic servo motor that operates the clutch valve. The clutch on state that activates the motor and the clutch off state that deactivates it are easy.
It is an object of the present invention to provide a control device with a simple configuration that can be reliably obtained. Hereinafter, one embodiment of the present invention will be described with reference to the drawings. Reference numeral 1 denotes a transmission case formed by combining two case halves 1a and lb divided in the longitudinal direction, and a transmission equipped with the transmission case is a hydraulic pump P.
and a hydraulic motor M.

The hydraulic pump P has a pump cylinder 4 that is penetrated by an input shaft 2 and spline-coupled 3 thereto, and has a large number of cylinder holes 5 arranged in an annular arrangement surrounding the rotation center of the pump cylinder 4. Pump plungers 6, 6, . . . are slidably connected to each other.

Power from an engine (not shown) is transmitted to the input shaft 2 via a flywheel 7. On the other hand, the hydraulic motor M is
It has a motor cylinder 8 arranged to concentrically surround the pump cylinder 4 and rotate relative to it, and a large number of annular arrays arranged around the rotation center of the motor cylinder 8. Motor plungers 10, 10... are slid into the cylinder holes 9, 9..., respectively.

A pair of support shafts 11 are provided on both axial end surfaces of the motor cylinder 8.
1V protrudes, one support shaft 11 is connected to the end wall of the right case half 1b through a ball bearing 12, and the other support shaft 1V is connected to the end of the left case half 1a through a needle bearing 13. each supported by a wall.

A stop ring 14 that clamps the inner race 12a of the ball bearing 12 together with the motor cylinder 8 is engaged with the outer end of one of the support shafts 11, and another stop ring is engaged with the outer end of the outer race 12b. 15 is the right case half 1b
is engaged with the annular recess 16 on the outer surface of the end wall of the outer race 12b, and is removably fixed to the right case half 1b by a bolt 18 or a presser plate 17 that abuts the outer end of the outer race 12b. Right case half 1
Axial movement relative to b is prevented. The other support shaft 1V is integrally formed with a gear 19 to serve as an output shaft, and the output of the hydraulic motor M is taken out from the gear 19 and transmitted to the differential gear device 21 via the intermediate gear 20. It's summery.

A pump swash plate 22 inclined at a certain angle with respect to each pump plunger 6 is fixed inside the motor cylinder 8, and a sliding piece 6a that can smoothly slide on the surface of this pump swash plate 22 is attached to each pump plunger. The pump swash plate 22 is swingably attached to the spherical end of the pump cylinder 6, and thus the pump swash plate 22 can give reciprocating motion to each pump plunger 6 as the pump cylinder 4 rotates, thereby repeating the suction and discharge strokes.

In addition, a motor swash plate 23 facing the motor plunger 10 is rotatably supported on the mission case 1 via a pair of trunnion shafts 24 protruding from both outer sides of the motor swash plate 23, and the surface of the motor swash plate 23 is smooth. A sliding piece 10a that can be slid on is swingably attached to the spherical end of each motor plunger 10, and thus the motor swash plate 23 causes each motor plunger 10 to reciprocate and expand as the motor cylinder 8 rotates. and the contraction stroke can be repeated.

The stroke of the motor plungers 10 can then be adjusted steplessly from zero to the maximum by tilting the motor swash plate 23 from an upright position perpendicular to each motor plunger 10 to the maximum tilted position shown. A hydraulic closed circuit is formed between the hydraulic pump P and the hydraulic motor M by a distribution panel D and a distribution ring 25, which will be described later.

Therefore, when the pump cylinder 4 is rotated from the input shaft 2,
Cylinder hole 5 that accommodates the pump plunger 6 in the discharge stroke
The high-pressure hydraulic oil discharged from the cylinder hole 9 that accommodates the motor plunger 10 on the expansion stroke is fed to the cylinder hole 9 that accommodates the motor plunger 10 on the contraction stroke.
The hydraulic oil discharged from the pump plunger 6 in the suction stroke
During this period, the reaction torque that the pump plunger 6 in the discharge stroke applies to the motor cylinder 8 via the pump swash plate 22, and the reaction torque that the motor plunger 10 in the expansion stroke receives from the motor swash plate 23. The motor cylinder 8 is rotated by the sum of . in this case,
The gear ratio of the motor cylinder 8 to the pump cylinder 4 is given by the following equation.

As is clear from the above equation, by changing the capacity of the hydraulic motor M from zero to a certain value, the gear ratio can be changed from 1 to a certain required value. Incidentally, since the capacity of the hydraulic motor M is determined by the stroke of the motor plunger 10, the gear ratio can be changed from l to a certain value by tilting the motor swash plate 23 from the upright position to a certain inclination angle as described above. It can be adjusted steplessly.A hydraulic servo motor S1 is provided in the transmission case 1 for tilting the motor swash plate 23.The motor cylinder 8 is divided into first to fourth parts in the axial direction. Consists of 8a to 8d.

The first portion 8a has a cup shape, is integrally provided with the output shaft 1V at its outer end, and supports the pump swash plate 22.

The second portion 8b has a cylindrical shape, and a support hole 9a for the motor plunger 10 in the cylinder hole 9 is provided along the entire length in the peripheral wall thereof, and the pump cylinder 4 is accommodated in the hollow portion thereof.

The third portion 8c has a disk shape, and the fourth portion 8d has a ring shape, and a series of motor hydraulic chambers 9b having a slightly larger diameter than the support hole 9a of the cylinder hole 9 are provided in these, and the third portion 8c A distribution board D is constituted by the central disc-shaped portion.
A connecting flange 26 is integrally provided on the first portion 8a at an end opposite to the second portion 8b, and the flange 26 is tightly fitted into a positioning recess 27 on the end face of the second portion 8b opposite thereto. The second part 8b is connected by the main connecting bolt 28.
sticks to.

Further, the second, third and fourth portions 8b, 8c and 8d are positioned with respect to each other by inserting dowel pins 29 and 30 into their respective joint portions, and a plurality of connecting bolts 31 are used to connect the second and fourth portions. 8b and 8d are tightly connected, and the third portion 8c is firmly held between them, and thus the first
-4 parts 8a-8d are joined together.

A fixed shaft 35 passing through the support shaft 11 of the motor cylinder 8 is connected to the holding plate 17 via a pin 36, and a distribution ring 25 in contact with the distribution plate D is attached to the inner end of the fixed shaft 35 in an eccentric manner. The distribution ring 25 partitions the hollow portion 37 of the fourth portion 8d of the motor cylinder 8 into an inner high pressure chamber 37a and an outer low pressure chamber 37b.

On the other hand, discharge and suction boats 38 and 39 are bored in the distribution board D, and the discharge boats 38 connect the cylinder hole 5 of the pump plunger 6 in the discharge stroke and the high pressure chamber 37.
A is in communication with the cylinder hole 5 of the pump plunger 6 in the suction stroke by the suction boat 39 and the low pressure chamber 3.
7b are communicated with each other. Further, the distribution board D has a large number of communication boats 40, 40, . . . extending radially. The motor hydraulic chambers 9b, 9b of the motor cylinder 8 are opened by these holes.
The one on the high pressure side is communicated with the high pressure chamber 37a, and the one on the low pressure side is communicated with the low pressure chamber 37b.
Therefore, when the pump cylinder 4 rotates, the high pressure hydraulic oil generated by the discharge stroke of the pump plunger 6 is transferred from the discharge boat 38 to the high pressure chamber 37a, and then via the communication boat 40 in communication with the high pressure chamber 37a to the motor for the expansion stroke. It flows into the motor hydraulic chamber 9b of the plunger 10 and the plunger 1
On the other hand, the hydraulic oil discharged by the motor plunger 10 in the contraction stroke is returned to the cylinder hole 5 of the pump plunger 6 in the suction stroke via the communication boat 40 communicating with the low pressure chamber 37b and the suction boat 39. However, due to such circulation of the hydraulic oil, power is transmitted from the hydraulic pump P to the hydraulic motor M as described above.

The fixed shaft 35 is formed hollow with a center hole 41, and a plurality of (two in the figure) short-circuit boats 42 are provided on the side wall of the fixed shaft 35.
, 43 are drilled.

The inner ends of these short-circuit boats 42 and 43 are connected to the high pressure chamber 37a through the center hole 41, and their outer ends are connected to the low pressure chamber 37b through the outer grooves 44 and 45 of the fixed shaft 35. The short-circuit boats 42 and 43 are connected to the center hole 4
The clutch valve 48 is opened and closed by rightward and leftward movement of a piston-type clutch valve 48 that slides into the clutch valve 1. That is, the clutch valve 48
is in the rightward movement position, the short-circuit boats 42 and 43 are opened to communicate between the two chambers 37a and 37b, and the hydraulic oil discharged from the discharge boat 38 of the distribution panel D is immediately transferred to the suction boat 3.
9 and the supply of hydraulic oil to the hydraulic motor M is not carried out, so the so-called clutch, which disables the hydraulic motor M,
When the clutch valve 48 is turned to the OFF state and the short-circuit boats 42 and 43 are both closed by moving the clutch valve 48 to the left, the hydraulic oil is circulated from the hydraulic pump P to the motor M, so the clutch is turned ON. . At an intermediate position of the clutch valve 48 between them, circulation of hydraulic oil occurs depending on the opening degree of the short-circuit boats 42 and 43, resulting in a half-clutch state, and the clutch valve 48 is in a half-clutch state.
It is effective to widen the half-clutch state area within the sliding stroke of 8 to obtain a smooth start of the vehicle. For this reason, in the illustrated example, the opening centers of the short-circuit boats 42 and 43 into the center hole 41 are offset from each other in the sliding direction of the clutch valve 48. Furthermore, in the illustrated example, the clutch valve 48
A tapered surface 49 is formed on the outer periphery of the end of the short-circuit boat 42, 43, so that the shorting boats 42, 43 can be opened and closed slowly, and the clutch switching operation can be performed more smoothly. A valve rod 50 is screwed onto the tip of the clutch valve 48, and its spherical end 50
An umbrella-shaped valve body 51 is swingably connected to a, and this valve body 5
1 is a distribution board D so as to close the discharge boat 38 when the clutch valve 48 moves to the left beyond the clutch-on position.
can be closely attached to. The discharge boat 38 is closed by the valve body 51 when the motor swash plate 23 is placed in an upright position and the gear ratio is set to l:1. The motor cylinder 8 can be mechanically driven via the pump plunger group 6 and the pump swash plate 22, so that the thrust applied to the motor swash plate 23 by the motor plunger 10 disappears, reducing the burden on each part due to the thrust. It can be reduced. For sliding operation of the clutch valve 48, a hydraulic servo motor S2 is built into the fixed shaft 35.

A replenishment pump F is equipped on the outside of the left case half 1a,
The pump is driven by the input shaft 2 and draws oil from an oil reservoir (not shown) to generate hydraulic oil at a constant pressure. The discharge boat 38 of the distribution board D and the low pressure chamber 3 are connected via the passage 53 and the check valves 54 and 55.
7b, respectively. Therefore, the hydraulic pump P
When hydraulic oil leaks from the hydraulic closed circuit of the hydraulic motor M, the leaked amount can be automatically replenished from the replenishment pump F. As described above, according to the present invention, the fixed shaft supporting the distribution ring is formed hollow, and a short-circuit boat is bored in the side wall of the fixed shaft for communicating between the low-pressure chamber and the high-pressure chamber, and the short-circuit boat is provided in the hollow part. Since a sliding piston type clutch valve that opens and closes and a servo motor that operates it are installed, the clutch valve can be operated easily and as desired by adjusting the input to the servo motor, and therefore the short-circuit boat can be opened and closed. Not only that, but the opening can be adjusted freely, and desired states such as clutch-on, clutch-off, and half-clutch can be accurately obtained, and when applied to a car, it can start and stop extremely smoothly. Furthermore, by incorporating the clutch valve and its servo motor into the fixed shaft, they are integrated into a unit, and as a result, the transmission can be easily assembled and downsized.

[Brief explanation of drawings]

The drawing is a longitudinal sectional side view of a hydraulic transmission equipped with the device of the present invention. 4...Pump cylinder, 8...Motor cylinder, 25...Distribution ring, 35...
Fixed shaft, 37a... High pressure chamber, 37b...
・Low pressure chamber, 38...Discharge boat, 39...
... Suction boat, 40 ... Communication boat, 41.
...Center hole as hollow part of fixed shaft, 42, 43
...Short-circuit boat, D...Distribution board, M.
...Hydraulic motor, P...Hydraulic pump, S
,······Servomotor.

Claims (1)

[Scope of Claims] 1. A hydraulic closed circuit is formed between a swash plate type hydraulic pump and a swash plate type hydraulic motor, and the hydraulic closed circuit connects suction and discharge ports of the hydraulic pump and a plurality of communication ports of the hydraulic motor. a distribution board that is open on one end surface and rotates together with the motor cylinder of the hydraulic motor; a high pressure chamber that is supported by a fixed shaft and is provided on one end surface of the distribution board and communicates between the discharge port and the communication port on the high pressure side; In a hydraulic transmission comprising a distribution ring defining a low pressure chamber that communicates between the suction port and the communication port on the low pressure side, the fixed shaft is formed hollow, and the low pressure chamber and the high pressure are connected to the side wall of the fixed shaft. Control of a hydraulic transmission, in which a short-circuit port communicating between chambers is bored, and a sliding piston-type clutch valve for opening and closing the short-circuit port and a hydraulic servo motor for operating the clutch valve are disposed in the hollow part. Device. 2. A plurality of short-circuit ports are provided, and the ports are offset from each other in the sliding direction of the clutch valve.
A control device for a hydraulic transmission according to claim 1. 3. The control device for a hydraulic transmission according to claim 1, wherein the clutch valve has a valve body at its tip that closes the discharge port at the forward limit after the short-circuit port is closed.