JPH04283131A - Engine - Google Patents

Abstract

PURPOSE:To provide an engine which is simple in its structure and compact in its size and by which wide applicability is available by incorporating a transmission in an integrated manner, and extending two output shafts. CONSTITUTION:There is provided, on the out side face of a crank-case wall 6b in an integrated manner, a transmission case 19 containing a hydraulic continuously variable transmission 22 which is composed of a hydraulic pump 20 and a hydraulic motor 21, and a cam shaft 13 in a crank case 6 is made as the driving shaft 23 of the hydraulic pump 20 by extending it in the transmission case 19 through the crank case wall 6b, and at the same time, the output shaft 24 of the hydraulic motor 21 is extended outward from the transmission case 19. And also there is provided an oil passage for connecting the hydraulic pump 20 to the hydraulic motor 21 in the crank case wall 6b.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention incorporates a transmission into one unit and outputs output directly from the crankshaft.
The present invention relates to an engine for a work vehicle, for example, which can be taken out through a transmission.

0002

[Prior Art] For example, in a work vehicle such as a riding lawn mower, the power of the mounted engine is transmitted to the wheels and used to drive the vehicle, and is also transmitted to the work machine such as the lawn mower to perform work. Used for machine driving. Usually, the above-mentioned engine has one output shaft, and within a power transmission system connected to this output shaft and separated from the engine, the power is divided into one for driving the vehicle and one for driving the work equipment. 12862
Japanese Patent No. 0 discloses an engine configured as an integrated drive unit (engine/transaxle complex) including an output shaft for driving a vehicle and an output shaft for driving a working machine.

[0003] In this drive unit, the transaxle is disposed laterally in a transaxle housing that is integrally connected to the engine housing, and pressure oil from a variable hydraulic pump provided in the engine body is supplied to the transaxle housing. The hydraulic power is supplied to a hydraulic motor provided therein, which drives the transaxle via a reduction mechanism and a differential mechanism also provided within the transaxle housing. On the other hand, the crankshaft of the engine extends downward from the engine main body at right angles to the transaxle, and a working tool connected to the working vehicle is driven from this crankshaft via a belt.

0004

[Problems to be Solved] However, since the above drive unit is directly integrated with the transaxle, the installation location on the work vehicle is limited, and it is applicable only to a specific work vehicle, depending on the model of the work vehicle. It lacks versatility, as the specifications must be changed accordingly. Furthermore, the structure is relatively complicated, and the overall size tends to be large.

[0005]

[Means and operations for solving the problems] The present invention has been made in view of the above circumstances, and the engine of the present invention has a hydraulic pump and a hydraulic motor on the outer surface of the crankcase wall. A transmission case containing a step change mechanism is attached, and a camshaft in the crankcase extends through the crankcase wall and into the transmission case to serve as a drive shaft for the hydraulic pump, and also serves as a drive shaft for the hydraulic pump. One end of an output shaft of the crankcase extends outside from the transmission case, and an oil passage connecting the hydraulic pump and the hydraulic motor is provided in the crankcase wall.

[0006] In this engine, engine power can be extracted directly from the crankshaft, and power that has been changed in speed by a hydraulic continuously variable transmission mechanism can be extracted from an output shaft of a hydraulic motor protruding from a transmission case. Therefore, when using this engine as a prime mover for a work vehicle,
The crankshaft may be connected to the working machine drive system, and the motor output shaft may be connected to the vehicle travel system.

The hydraulic pump and hydraulic motor that make up the hydraulic continuously variable transmission mechanism are housed in one case and attached to the crankcase wall, and the camshaft also serves as the drive shaft of the hydraulic pump and is mounted inside the crankcase wall. An oil passage connecting the hydraulic pump and the hydraulic motor is formed, and the crankcase wall also serves as the oil passage configuration plate (distributor plate) of the hydraulic continuously variable transmission mechanism, so that the oil passage connecting the hydraulic pump and the hydraulic motor is The structure is simplified, and the entire engine incorporating the hydraulic continuously variable transmission can be made smaller.

[0008]

Embodiment FIG. 1 is a sectional view of an engine 1 according to an embodiment of the present invention. This engine 1 is constructed by integrally assembling a transmission 3 to an engine body 2. 4 is a cylinder head, 5 is a cylinder block, and 6 is a crankcase. The crankcase 6 is the cylinder block 5
The case main body 6a is formed integrally with the main body 6a and is open toward one side, and the case lid 6a closes the open portion.

A crankshaft 9, which is rotatably driven by a piston 8 via a connecting rod 7, is rotatably supported by the case body 6a and case lid 6b, and has both ends protruding outward from the crankcase 6, and is connected to the case body. A flywheel 10, a fan 11, a recoil starter 12, etc. are provided at the end protruding from the side 6a. Inside the crankcase 6, a camshaft 13 connected to the crankshaft 9 through a gear is installed parallel to the crankshaft 9 so as to be freely rotatable. is activated. 16 is an intake passage, 17 is a carburetor, and 18 is an exhaust passage.

The transmission 3 is housed in a transmission case 19 that is integrally attached to the outer surface of the case lid 6b of the crankcase 6, and includes a swash plate type hydraulic pump 20 and a swash plate type hydraulic motor 21. Hydraulic continuously variable transmission mechanism 2 having
It consists of 2. A drive shaft of the hydraulic pump 20, ie, a pump shaft 23, is integral with the camshaft 13. That is, the camshaft 13 extends into the transmission case 19 through the case lid 6b, and its tip is rotatably supported by the transmission case 19, and this extended portion serves as the pump shaft 23. An output shaft 24 of a hydraulic motor 21 provided close to and directly below the hydraulic pump 20 is arranged parallel to the pump shaft 23, and is rotatably supported at both ends by a case lid 6b and a transmission case 19, respectively. , and one end protrudes from the transmission case 19 to the outside. Above the transmission case 19, one end of the crankshaft 9 extends directly from the case lid 6b.

FIG. 2 is an enlarged sectional view of the transmission 3. As shown in FIG. The hydraulic pump 20 includes a cylinder block 25 attached to the pump shaft 23 so as to rotate together with the cylinder block 25, and the cylinder block 25 has a plurality of cylinders 26 parallel to the pump shaft 23 arranged around a circumference concentric with the pump shaft 23. They are placed at equal intervals on the top. A piston 28 biased rightward by a spring 27 is slidably fitted into the cylinder 26 . A swash plate 29 is provided on the right side of the cylinder block 25 to face it. The tip of the piston 28 biased by the spring 27 contacts and presses the swash plate 29, and the swash plate 29 is supported by a swash plate support 31 via rollers 30 arranged in an annular manner in contact with the back surface of the swash plate 29. It is accepted by When the camshaft 13 is driven by the crankshaft 9 and rotates during engine operation, and the pump shaft 23 integrated with the camshaft 13 rotates, the cylinder block 25 rotates together with the pump shaft 23. At this time, piston 28
The swash plate 29, which is being pushed by
The surface formed by 0 and therefore also the surface of the swash plate 29 is
Since it is inclined with respect to the axis of the pump shaft 23, a stroke movement of the piston 28 occurs in response to rotation. The bottom of the cylinder 26 is connected to the cylinder block 2 through the inlet/outlet 32.
5, and the left end surface is in sliding contact with a valve plate 33 provided on the case lid 6b. The case lid 6b has an oil passage 34 connecting the hydraulic pump 20 and the hydraulic motor 21.
a, 34b, and the valve plate 33 is provided with a valve hole that communicates the inlet/outlet 32 with the oil passage 34a or the oil passage 34b at an appropriate rotational position, so that the above-mentioned stroke movement of the piston 28 As a result, oil is sucked into the piston 28 from one oil passage 34b, then pressurized and discharged to the other oil passage 34a.

The hydraulic motor 21 has basically the same structure as the hydraulic pump 20, and includes a cylinder block 35,
It includes a cylinder 36, a spring 37, a piston 38, and a swash plate 39. Swash plate 39 is supported by transmission case 19 via balls 40 and thrust plate 41. The cylinder block 35 is fixed to the output shaft 24. The cylinder block 35 is in sliding contact with a valve plate 42 similar to the valve plate 33 in the hydraulic pump 20, and oil is forced into the cylinder 36 through the oil passages 34a, 34b and the valve plate 42 depending on the rotational position of the cylinder 36. or discharged from the cylinder 36 to the piston 38
gives a stroke motion to. The oil pressurized into the cylinder 36 is the pressure oil pumped into the oil passage 34a by the hydraulic pump 20. Since the piston 38 is in contact with the swash plate 39 and is guided by the swash plate 39, the stroke movement of the piston 38 causes the cylinder block 3 to move.
5 rotates, which causes the output shaft 24 to rotate. That is, the rotation of the pump shaft 23 is transmitted to the output shaft 24 via the oil pressure generated by the hydraulic pump 20.

The swash plate support 31 of the hydraulic pump 20 is tiltably pivoted to the transmission case 19, and the swash plate support 31 is tilted by an operating device (not shown) to adjust the inclination angle of the swash plate 29. It is now possible to change. Changing the inclination angle of the swash plate 29 changes the discharge capacity of the hydraulic pump 20, which changes the rotational speed of the output shaft 24 of the hydraulic motor 21. Therefore, the gear ratio between the pump shaft 23 and the output shaft 24 can be changed steplessly. can be changed accordingly.

[0014] The engine 1 configured in this way has the following features:
It has two output shafts extending to the outside, namely, the crankshaft 9 and the output shaft 24 of the hydraulic motor 21. Engine power can be extracted directly from the crankshaft 9, and the hydraulic pressure can be continuously controlled through the output shaft 24. Engine power that has been changed in speed by the speed change mechanism 22 can be taken out. When the engine 1 is used as a prime mover for a work vehicle such as a riding lawn mower, the output shaft 24 is connected to the vehicle's travel drive system, and the travel speed is controlled by the hydraulic continuously variable transmission mechanism 22. The shaft 9 is connected to the working machine drive system via a suitable speed reduction mechanism if necessary.

The hydraulic pump 20 and the hydraulic motor 21 constituting the hydraulic continuously variable transmission mechanism 22 are compactly housed in the transmission case 19 and attached to the case lid 6b of the crankcase 6, and the camshaft 13 is connected to the hydraulic pump. 20, and an oil passage 34 connecting the hydraulic pump 20 and the hydraulic motor 21 is formed in the case lid 6b, and the case lid 6b also serves as an oil passage configuration plate of the hydraulic continuously variable transmission mechanism 22. Therefore, the structure of the transmission 3 is simplified, and even though the transmission 3 is integrated, the engine 1 as a whole is relatively small. Therefore, this engine 1
It is easy to install on a work vehicle, and the installation location can be selected with a relatively large degree of freedom.

[0016]

Effects of the Invention According to the present invention, the structure of the transmission integrated into the engine is simplified, and even though the transmission is incorporated and two output shafts are provided, the overall engine size is relatively small. It becomes small. Therefore, this engine is easy to install on a work vehicle, and the installation location can be selected with a relatively large degree of freedom, making it highly versatile.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of the transmission in FIG. 1;

[Explanation of symbols]

1...Engine, 2...Engine body, 3...Transmission device, 4...
Cylinder head, 5... Cylinder block, 6... Crank case, 7... Connecting rod, 8... Piston, 9... Crankshaft,
10... flywheel, 11... fan, 12... recoil starter, 13... camshaft, 14... intake valve, 15... exhaust valve, 16... intake passage, 17... carburetor, 18... exhaust passage, 1
9... Transmission case, 20... Hydraulic pump, 21... Hydraulic motor, 22... Hydraulic continuously variable transmission mechanism, 23... Pump shaft, 24...
Output shaft, 25...Cylinder block, 26...Cylinder, 2
7... Spring, 28... Piston, 29... Swash plate, 30...
Roller, 31...Swash plate support, 32...Inlet/outlet, 33...Valve plate, 34...Oil passage, 35...Cylinder block, 36...Cylinder, 37...Spring, 38...Piston, 39...Swash plate,
40...Ball, 41...Thrust plate, 42...Valve plate.

Claims (1)

[Claims] Claim 1: A transmission case containing a hydraulic continuously variable transmission mechanism consisting of a hydraulic pump and a hydraulic motor is attached to the outer surface of the crankcase wall, and a camshaft in the crankcase is passed through the crankcase wall to Extending into the transmission case to serve as a drive shaft for the hydraulic pump, and extending one end of the output shaft of the hydraulic motor to the outside from the transmission case, and connecting the hydraulic pump and the hydraulic motor. An engine characterized in that an oil passage is provided within the wall of the crankcase.