JPS6123411B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic transmission device, particularly a hydraulic pump having a plurality of pump plungers arranged in an annular manner slidingly connected to a pump cylinder, and a hollow motor cylinder surrounding the pump cylinder having the same arrangement in an annular arrangement. A hydraulic motor formed by sliding together a large number of motor plungers is hydraulically connected, and a pump swash plate is fixed inside the motor cylinder to give reciprocating motion to the pump plunger as it rotates relative to the pump cylinder,
Further, a motor swash plate that provides reciprocating motion to the motor plunger as the motor cylinder rotates is tiltably supported via a trunnion shaft in a transmission case that houses the motor cylinder and rotatably supports the motor cylinder, The motor swash plate is tilted from an upright position to a predetermined inclined position to adjust the reciprocating stroke of the motor plunger from zero to the maximum, thereby reducing the speed ratio, that is, the rotation ratio of the pump cylinder and motor cylinder to 1 (TOP state). ) to the maximum value (LOW state).The purpose of this transmission is to raise the motor swash plate from a tilted position during a speed increase operation to raise the motor swash plate from a tilted position. The purpose of the present invention is to provide an upright positioning device for a motor swash plate, which has a simple structure and is easy to manufacture, and which can accurately stop the motor swash plate in the upright position and obtain a proper TOP state. The transmission case is divided into two case halves on a plane including one end surface of the motor swash plate, and the inner wall of one of the case halves is placed in contact with the one end surface of the motor swash plate. A stopper having a stopper surface capable of holding the motor swash plate in the upright position is integrally provided, and the stopper surface is formed continuously with the dividing surface of the one case half without a step.

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 1b divided in the longitudinal direction, and a transmission device equipped therewith is a hydraulic pump P.
and a hydraulic motor M.

The hydraulic pump P includes a pump cylinder 4 which is passed through the input shaft 2 and is spline-coupled 3 thereto.
and a large number of pump plungers 6, 6..., which are slidably engaged with a large number of annularly arranged cylinder holes 5, 5... provided in the pump cylinder 4 so as to surround its center of rotation, and an input shaft. Power from an engine (not shown) is transmitted to 2 via a flywheel 7. On the other hand, the hydraulic motor M is
A motor cylinder 8 is arranged so as to be able to concentrically surround the pump cylinder 4 and rotate relative to it, and a large number of cylinders arranged in an annular arrangement surrounding the rotation center of the motor cylinder 8. It is composed of a large number of motor plungers 10, 10, . . ., which are slidably engaged with holes 9, 9, .

A pair of support shafts 11 and 11' are protruded from both axial end surfaces of the motor cylinder 8, and one support shaft 1
1 is supported by the end wall of the right case half 1b via a ball bearing 12, and the other support shaft 11' is supported by the end wall of the left case half 1a via a needle bearing 13. A retaining ring 14 that clamps the inner race 12a of the ball bearing 12 together with the motor cylinder 8 is attached to the outer end of one of the support shafts 11.
is locked, and another stop ring 15 that is locked to the outer edge of the outer race 12b is attached to the right case half 1.
a presser plate 17 that is engaged with the annular recess 16 on the outer surface of the end wall of b and further abuts the outer end of the outer race 12b;
is removably fixed to the right case half 1b by bolts 18, thus preventing the ball bearing 12 and the support shaft 11 from moving in the axial direction with respect to the right case half 1b.

The other support shaft 11' 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 getting old.

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 4, and as the pump cylinder 4 rotates, the pump swash plate 22 can reciprocate each pump plunger 6 to repeat the suction and discharge strokes.

A motor swash plate 23 is provided opposite to each motor plunger 10, and this motor swash plate 23 rotates a pair of trunnion shafts 24 protruding from both outer sides between both case hemispheres 1a and 1b of the mission case 1. The motor plungers 10 can be freely tilted from an upright position perpendicular to each motor plunger 10, as shown by chain lines, to a maximum tilt position, as shown by solid lines, thereby making the stroke of the motor plungers 10 stepless from zero to maximum. Can be adjusted.

In the present invention, in order to define the upright position of the motor swash plate 23, both case halves 1a, 1b of the transmission case 1 are placed on a plane including the motor cylinder 8 side end surface 23a of the motor swash plate 23 in the upright state. A stopper 46 is integrally provided on the inner wall of the right case half 1b and has a stopper surface 46a that is continuous with the dividing surface without any step and can come into contact with the end surface 23a of the motor swash plate 23. It is.

Therefore, the motor swash plate 23 can be held in a predetermined upright position by coming into contact with the stopper 46, and in particular, the stopper 46, which is integrated with the transmission case, can hold the motor swash plate 23 without relaying any member.
3 is directly supported, so its upright position can be accurately obtained.

A hydraulic closed circuit is formed between the hydraulic pump P and the hydraulic motor M via a distribution panel D and a distribution ring 25, which will be described later. Pump cylinder 4 from input shaft 2
When rotating the pump plunger 6 in the discharge stroke
High-pressure hydraulic oil discharged from the cylinder hole 5 housing the motor plunger 10 is fed to the cylinder hole 9 housing the motor plunger 10 on the expansion stroke, while being discharged from the cylinder hole 9 housing the motor plunger 10 on the contraction stroke. The hydraulic oil is returned to the cylinder hole 5 that accommodates the pump plunger 6 on the suction stroke, and during this period, the reaction torque that the pump plunger 6 on the discharge stroke gives to the motor cylinder 8 via the pump swash plate 22;
The motor plunger 10 in the expansion stroke is connected to the motor swash plate 2.
The motor cylinder 8 is rotated by the sum of the reaction torque received from the motor cylinder 3.

In this case, the gear ratio of the motor cylinder 8 to the pump cylinder 4 is given by the following equation.

Speed ratio = rotation speed of pump cylinder 4 / rotation speed of motor cylinder 8 = 1 + capacity of hydraulic motor M / capacity of hydraulic pump P As is clear from the above equation, change the capacity of hydraulic motor M from zero to a certain value. For example, 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 1 to a certain value by tilting the motor swash plate 23 from the upright position to a certain inclination angle as described above. Can be adjusted in stages. A hydraulic servo motor S ₁ is provided in the mission case 1 for tilting the motor swash plate 23 .

The motor cylinder 8 is composed of first to fourth parts 8a to 8d divided in the axial direction.

The first portion 8a is cup-shaped, integrally provided with the output shaft 11' having a gear 19 at its outer end, and supports the pump swash plate 22 at its inner end surface.

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 of the second portion 8b, 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 these have a support hole 9a of the cylinder hole 9.
A series of motor hydraulic chambers 9b having a slightly larger diameter are provided, and a distribution board D is formed by the central disc-shaped portion of the third portion 8c.

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 portions 8a and 8b are coaxially aligned. And this connecting flange 2
6 to the second portion 8b by a plurality of connecting bolts 28.
sticks to.

Also, the second, third and fourth portions 8b, 8c, 8
d has knock pins 29, 30 at their respective joints.
The second and fourth parts 8b, 8 are inserted into each other and positioned mutually, and the second and fourth parts 8b, 8 are connected by a plurality of connecting bolts 31.
d are tightly connected, and the third portion 8c is firmly held between them, thus the first to fourth portions 8a
~8d are combined together.

The input shaft 2 has its outer end supported at the center of the support 11' via a needle bearing 32, and its inner end supported at the center of the distribution board D via a needle bearing 33. A compression spring 57 is housed in an annular spring chamber 56 formed adjacent to the spline joint 3 between the opposing peripheral surfaces of the input shaft 2 and the pump cylinder 4, and the right end of the spring 57 is locked to the pump cylinder 4. Seat plate 58
and a seat plate 59 whose left end is locked to the input shaft 2.
make contact with each other elastically. On the other hand, input shaft 2
A stopper plate 60 facing the inner end surface of the motor cylinder 8 is engaged with a portion protruding from the left end surface of the pump cylinder 4, and a needle thrust bearing 61 is interposed between these opposing surfaces. Therefore, the elastic force of the spring 57 presses the pump cylinder 4 against the distribution board D via the seat plate 58 to prevent oil leakage from their rotating and sliding parts, and the reaction force of the elastic force is transmitted to and supported by the motor cylinder 8 via the seat plate 59, input shaft 2, stopper plate 60 and needle thrust bearing 61.

The support plate 17 has a support shaft 1 of the motor cylinder 8.
A fixed shaft 35 passing through D 1 is connected via a pin 36 , and a distribution board D is connected to the inner end of this fixed shaft 35 .
A distribution ring 25 in contact with the motor cylinder 8 is eccentrically supported by the distribution ring 25.
The hollow portion 37 of d is divided into an inner chamber 37a and an outer chamber 37b. On the other hand, the distribution board D is provided with discharge and suction ports 38 and 39, and the discharge port 38 communicates between the cylinder hole 5 of the pump plunger 6 in the discharge stroke and the inner chamber 37a, and the suction port 39 between the cylinder hole 5 of the pump plunger 6 in the suction stroke and the outer chamber 3
7b. Further, the distribution board D is provided with a large number of communication ports 40, 40, . . . extending radially, and these allow the motor hydraulic chambers 9b, 9b, . . . will be communicated to.

Therefore, when the pump cylinder 4 rotates, the high pressure hydraulic oil generated by the discharge process of the pump plunger 6 is transferred from the discharge port 38 to the inner chamber 37a.
Furthermore, the hydraulic oil flows into the motor hydraulic chamber 9b of the motor plunger 10 in the expansion process through the communication port 40 communicating with it, giving a thrust to the plunger 10, while the hydraulic oil discharged by the motor plunger 10 in the contraction process flows outside. It is returned to the cylinder hole 5 of the pump plunger 6 in the suction stroke through the communication port 40 and the suction port 39 that communicate with the chamber 37b, and due to this circulation of the hydraulic oil, the oil is supplied from the hydraulic pump P to the hydraulic motor M as described above. Transmission takes place.

The fixed shaft 35 has a center hole 41 and a plurality of (two in the figure) short-circuit ports 42 passing through the side wall of the center hole 41.
43, the inner ends of these shorting ports 42 and 43 are connected to the inner chamber 37a through the center hole 41, and their outer ends are connected to the outer groove 4 of the fixed shaft 35.
4 and 45, and these shortened ports 42 and 43 are opened and closed by rightward and leftward movement of a clutch valve 48 that slides into the center hole 41. That is, when the clutch valve 48 is in the rightward movement position, the short-circuit ports 42 and 43 are opened to communicate between the inner and outer chambers 37a and 37b, and the hydraulic oil discharged from the discharge port 38 of the distribution board D is immediately discharged. Since the suction port 39 is short-circuited and hydraulic oil is not supplied to the hydraulic motor M, the hydraulic motor M becomes inactive, a so-called clutch-off state, and then the clutch valve 48 is moved to the left to short-circuit. When both ports 42 and 43 are closed, the hydraulic oil is circulated from the hydraulic pump P to the motor M, resulting in a clutch-on state.

A valve rod 50 is screwed onto the tip of the clutch valve 48, and an umbrella-shaped valve body 51 is swingably connected to its spherical end 50a.
8 can be brought into close contact with the distribution board D so as to close the discharge port 38 when it moves to the left beyond the clutch-on position. The discharge port 38 is blocked by the valve body 51 by making the motor swash plate 23 upright.
This is done when the pump is in the TOP state. This allows the pump plunger 6 to be hydraulically locked and the motor cylinder 8 to be mechanically driven from the pump cylinder 4 via the pump plunger 6 group and the pump swash plate 22. , Therefore, the thrust applied to the motor swash plate 23 of the motor plunger 10 disappears,
The burden on each part due to the thrust can be reduced.

For sliding operation of the clutch valve 48, a hydraulic servo motor _S2 is provided on the fixed shaft 35.

A replenishment pump F is installed on the outside of the left case half 1a, and the pump is driven by an input shaft 2 to suck oil from an oil reservoir (not shown) to generate hydraulic oil at a constant pressure. The discharge port 52 of this pump F is connected to the distribution panel D via an oil passage 53 in the input shaft 2 and then via check valves 54 and 55.
and the outer chamber 37b, respectively. Therefore, when hydraulic oil leaks from the hydraulic closed circuit of the hydraulic pump P and 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 transmission case is divided into two case halves on a plane including one end surface of the upright motor swash plate, and the inner wall of one of the case halves is Since a stopper having a stopper surface that can contact the one end surface of the motor swash plate and hold the motor swash plate in an upright position is integrally provided, when the motor swash plate stands upright, the end surface is integrally connected to the transmission case. The motor swash plate can be directly supported by the stopper to maintain its upright position, and the motor swash plate is positioned via a link mechanism connected to the swash plate, a servo mechanism for tilting the swash plate, etc. Compared to this, the positioning accuracy can be improved and a proper TOP state can always be obtained.

Further, since the stopper surface is formed continuously with no step on the dividing surface of the one case half,
At the same time as finishing the case half dividing surface, which is originally performed with high processing accuracy, the stopper surface can be accurately finished, making manufacturing simple and easy, and further improving the positioning accuracy of the upright position of the motor swash plate. Moreover, since the stopper can be cast integrally with the case half, there is no increase in the number of parts and the structure is extremely simple.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional side view of a hydraulic transmission equipped with the device of the present invention. 1...Mission case, 1a...Left case half, 1b...Right case half, 4...Pump cylinder, 6...Pump plunger, 8...Motor cylinder, 10...Motor plunger, 22... Pump swash plate, 23...motor swash plate, 23a...end face,
24...Trunion shaft, 46...Stopper, 46
a... Stopper surface, M... Hydraulic motor, P... Hydraulic pump.

Claims (1)

[Claims] 1 A hydraulic pump formed by sliding a large number of pump plungers arranged in an annular manner on a pump cylinder, and a hydraulic motor formed by sliding a large number of motor plungers arranged in an annular manner around a hollow motor cylinder surrounding the pump cylinder. A pump swash plate is fixedly connected to the motor cylinder and provides a reciprocating motion to the pump plunger as it rotates relative to the pump cylinder, and also accommodates the motor cylinder and rotatably supports it. A motor swash plate that provides reciprocating motion to the motor plunger as the motor cylinder rotates is tiltably supported in the transmission case via a trunnion shaft, and the motor swash plate is tilted from an upright position to a predetermined inclined position. In this hydraulic transmission device, the reciprocating stroke of the motor plunger is adjusted from zero to a maximum, and the transmission case is divided into two case halves on a plane including one end surface of the upright motor swash plate. A stopper is integrally provided on the inner wall of one of the divided case halves and has a stopper surface capable of abutting the one end surface of the motor swash plate and holding the motor swash plate in the upright position. An apparatus for vertically positioning a motor swash plate in a hydraulic transmission, characterized in that the stopper surface is formed continuously on the dividing surface of the one case half without any difference in level.