JP2872945B2 - Axle drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a configuration of an axle driving device integrated with an HST transmission, which is mounted as a transmission device for a traveling vehicle.

[0002]

2. Description of the Related Art Conventionally, in an L-shaped center section of an HST transmission, a position of a hydraulic motor mounting surface formed in a vertical portion thereof is lower than an axial center position of a pump shaft of a hydraulic pump installed in the horizontal portion. As a setting technique, a technique described in Japanese Utility Model Laid-Open No. 47-25681 is known. Also, an axle drive unit integrated with an HST transmission is known. For example, JP
This is like the technique described in JP-A-309821. In the above-mentioned prior art, an L-shaped center section fixed in an axle case is used as a pump mounting surface at a horizontal portion of the L-shaped center section, and a motor mounting surface is formed at a vertical portion perpendicular to the L-shaped center section. Formed on the surface. However, since the position of the pump mounting surface is set so as to coincide with an imaginary extension of the position of the axis of the motor shaft supported by the motor mounting surface, the tip position of the pump shaft protruding outside the axle case is As a result, the position of the belt transmission mechanism for inputting the engine power to the pump shaft becomes high, and it is difficult to lower the floor of the vehicle getting on and off.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned disadvantages of the prior art. By lowering the tip of the pump shaft, the position of the belt transmission mechanism is lowered.
An axle drive unit integrated with an HST transmission geared to a low-floor specification traveling vehicle is provided. Also, by lowering the position of the hydraulic pump mounting surface relative to the position of the motor shaft of the hydraulic motor, the axle case can be downsized,
This is to reduce the size of the entire axle drive unit integrated with the ST transmission.

[0004]

The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described. In claim 1, the axle case is formed by joining the upper axle case 1 and the lower axle case 2 up and down, and the L-shaped center section 3 is formed inside the axle case.
And fix the upper surface of the horizontal portion of the L-shaped center section 3 to the mounting surface 3b of the hydraulic pump constituting the HST transmission.
And L which is orthogonal to the pump mounting surface 3b.
In a configuration in which the outer surface of the vertical portion of the center section 3 is formed on the mounting surface 3a of the hydraulic motor of the HST transmission, the height of the joint fixing surface between the upper axle case 1 and the lower axle case 2 is L1, and the upper axle is The axial position of the motor shaft 12 of the hydraulic motor coincides with the joint fixing surface of the case 1 and the lower axle case 2, and the height of the pump mounting surface 3b is adjusted to the joint fixing surface of the upper axle case 1 and the lower axle case 2. Of the pump mounting surface 3b.
Mounting seats 1a and 1b constituting the contact fixing surface of the axle case
1c is joined to upper axle case 1 and lower axle case 2
This is deviated below the height L1 of the fixing surface .

In the second aspect, the axle case is formed by joining the upper axle case 1 and the lower axle case 2 up and down, and the L-shaped center section 3 is formed inside the axle case. Place it fixed on the lower surface,
The upper surface of the horizontal portion of the L-shaped center section 3 is
The mounting surface 3b of the hydraulic pump constituting the transmission is formed, and the outer surface of the vertical portion of the L-shaped center section 3 formed perpendicular to the pump mounting surface 3b is formed on the mounting surface 3a of the hydraulic motor of the HST transmission. In the configuration, the height of the joint fixing surface between the upper axle case 1 and the lower axle case 2 is L1
And the height L2 of the joint fixing surface of the L-shaped center section 3 to the lower surface of the upper axle case 1 is defined as
The joint-fixing surface of the lower axle case 2 is aligned with the axis of the motor shaft 12 of the hydraulic motor, and the joint-fixing surface of the L-shaped center section 3 to the lower surface of the upper axle case 1 is fixed to the pump mounting surface 3b. And the height L2 of the joint fixing surface of the L-shaped center section 3 to the lower surface of the upper axle case 1 is equal to the upper axle case 1 and the lower axle case 2
Are deviated below the height L1 of the joint fixing surface.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The problems to be solved and means to be solved by the present invention are as described above. Next, the configuration of the embodiment shown in the accompanying drawings will be described. FIG. 1 is a front sectional view of an axle drive device of the present invention, and FIG. 2 is a plan view of the same with an upper axle case 1 removed. The axle case is configured by dividing the upper axle case 1 and the lower axle case 2 into upper and lower parts by a horizontal division surface, in which the left and right axles 22 and 22 and the motor shaft 12 are vertically divided in a plane including the respective axes. doing. The motor shaft 12 and the axles 22 are supported by bearings supported on the joint surface between the upper axle case 1 and the lower axle case 2.

The pump shaft 11 is vertically supported by a bearing provided in the upper axle case 1 and a bearing metal formed in a bearing hole vertically formed in the L-shaped center section 3. A pulley is attached to a portion protruding from 1, and power is transmitted from a vertical crankshaft engine by a belt transmission mechanism. A hydraulic pump device is engaged with a portion where the pump shaft 11 projects into the upper axle case 1. The hydraulic pump device is disposed on the upper surface of the horizontal portion of the L-shaped center section 3, and includes a pump case 5, a pump piston 17, and a piston urging spring 19.
, A movable swash plate 7, and a thrust bearing 7 a that rotates together with the movable swash plate 7.

The pump case 5 slides and rotates in a contact state between the pump mounting surface 3b formed on the upper surface of the horizontal portion of the L-shaped center section 3 and the thrust bearing 7a, and pressurizes the working oil to make the L. Oil is supplied to the hydraulic motor device via an oil passage described later in the center section 3. The hydraulic motor device is arranged on the outer surface of the vertical portion of the L-shaped center section 3. The hydraulic motor device includes a motor case 6, a motor piston 18, a piston biasing spring 20, a fixed swash plate 8, and a thrust bearing 8a of the fixed swash plate 8. The hydraulic oil discharged from the hydraulic pump device is fed into the oil chamber formed by the motor case 6 and the motor piston 18, so that the motor case 6 is formed on the outer surface of the vertical portion of the L-shaped center section 3. Motor mounting surface 3
a and the thrust bearing 8a are slid and rotated in a contact state, and the motor case 6 is fitted with the motor shaft 12 in the engaged state.

The fixed swash plate 8 is vertically symmetrical and non-rotatably sandwiched between the upper and lower axle cases 1 and 2. And, with respect to the rotation direction of the pump shaft 11,
When the rotation direction of the motor shaft 12 is reversed, the fixed swash plate 8 can be fixed upside down. The L-shaped center section 3 is shown in FIG.
, The pump mounting surface 3
Fixing bolt holes for the upper axle case 1 are formed at three locations around the periphery of b as an abutment fixing surface for the axle case. In the three holes, three fixing bolts 13.14.1
Mounting seats 1a and 1 protruding downward from the joint surface of the upper axle case 1 and disposed in the lower axle case 2.
The L-shaped center section 3 is fixed by screwing into the screw holes b and 1c.

The lower ends of the mounting seats 1a, 1b, and 1c form a contact-fixing surface with respect to the pump mounting surface 3b of the L-shaped center section 3, and the upper axle case 1 and the lower axle case 2 are joined. The height of the fixing surface is the position of L1 shown in FIG. 1. Since the contact fixing surface protrudes downward from L1 and is arranged in the lower axle case 2,
The height of the joint fixing surface to the upper bottom surface of the axle case 1 in the form center section 3 becomes the position of L2, the abutment solid設面L-shaped center section 3 between L1 through L2 since the pump mounting surface 3b The hydraulic pump mounting surface 3b is lowered by the distance, and the pump shaft 11 erected on the pump mounting surface 3b is disposed at a low position. On the other hand, the vertical portion of the L-shaped center section 3 is greatly protruded upward, and the position of the motor shaft 12 of the hydraulic motor device mounted here is located higher than the horizontal portion of the L-shaped center section 3. The motor shaft 12 can have the same height as the height L1 of the joint fixing surface between the upper axle case 1 and the lower axle case 2. As a result, the hydraulic pump mounting surface 3b is disposed so as to be deviated below the axis of the motor shaft 12 of the hydraulic motor, and the hydraulic pump mounting surface 3b is located closer to the horizontal joint surface between the upper axle case 1 and the lower axle case 2. Are also displaced downward.

The L-shaped center section 3 is mounted on the mounting seats 1a, 1b, 1c of the upper axle case 1 by three mounting bolts 13, 14, 15 from below, and the lower axle case 1 is mounted on the upper axle case 1. When joining and fixing, the cylindrical oil filter 16 is attached to the lower axle case 2.
And the lower surface of the L-shaped center section 3 are interposed and supported. Similarly, in the embodiment shown in FIGS. 2 and 3, the vertical hole 3i formed in the vertical portion of the L-shaped center section 3 is formed.
-The blind plugs 4 for closing the lower end opening of 3j are interposed and fixed. As another construction, the blind plugs 4 are screwed and fixed directly to the lower surface of the L-shaped center section 3 without being interposed and supported between the lower axle case 2 and a vertical blind hole. It is good also as composition which closes 3i and 3j.

As shown in FIG. 2, a shift arm 30 is provided at a portion protruding from the outer upper surface of the upper axle case 1.
The rotation of the transmission arm 30 causes the transmission lever 35 to rotate, and the movable swash plate 7 is configured to rotate for shifting.
A closed circuit opening shaft 33 protrudes from the outer upper surface of the upper axle case 1, and a closed circuit opening arm 34 is fixed thereto. An eccentric pin 31 is provided at the lower end of the closed circuit opening shaft 33. By rotating the closed circuit opening arm 34, the eccentric pin 31 presses the check valve simultaneous operating rod 9, and the check valve pressing rod By simultaneously pressing the valves 40 and 43 and simultaneously opening the check valves 38 and 39, the closed circuit formed between the hydraulic pump device and the hydraulic motor device is opened in the axle case. This creates a neutral state in which the device does not rotate, or a state in which pressurized oil is not trapped in the closed circuit even when the device is rotated by traction from the hydraulic motor device side. Reference numeral 32 denotes a biasing spring that presses the closed-circuit open shaft 33 downward to press a detent mechanism formed on the lower surface of the closed-circuit open arm 34 and the upper surface of the boss of the upper axle case 1. , 42 and 41 are check valve pressing rods 40 and 4
3 is an urging spring that urges No. 3 in a releasing direction.

A gear 23 is engraved in the middle of the motor shaft 12, and the gear 23 is a large-diameter gear 24 of the counter shaft 21.
, And the small-diameter gear 25 of the counter shaft 21 meshes with the ring gear 26 of the differential gear device 27. The left and right axles 22 are driven by the differential gear device 27. Both the axles 22 and 22 and the counter shaft 21 and the motor shaft 12
Are also supported between the upper axle case 1 and the lower axle case 2. A brake drum 29 is engraved at the tip of the motor shaft 12, and a brake band 28 for braking the brake drum 29 is provided.

FIG. 3 is a side sectional view of a vertical portion of the L-shaped center section 3, FIG. 4 is a horizontal sectional view of a horizontal portion of the L-shaped center section 3, and FIG.
It is front sectional drawing in the part. The hydraulic pressure communicating with the check valve cases 36 and 37 is L-shaped center section 3.
And is communicated with the inside of the oil filter 16. Therefore, the hydraulic oil decreases in the closed circuit,
When a negative pressure is generated in the oil path on the low pressure side, one of the check valves 38 and 39 is opened, and the operating oil in the oil filter 16 is sucked into the closed circuit. In the horizontal portion of the L-shaped center section 3, the side into which the check valve cases 36 and 37 are inserted has a large diameter and becomes gradually smaller, and the L-shaped center section 3 made of an aluminum material has a hole formed at the time of casting. A pair of holes are formed, and the through holes are used to insert the check valve cases 36 and 37, and to form the side holes 3 forming a closed circuit.
g · 3h.

As shown in FIG. 5, arcuate oil channels 3c and 3d are formed in the pump mounting surface 3b so as to communicate with the lateral holes 3g and 3h. The kidney ports 3c and 3d are also formed by aluminum casting holes. The kidney ports 3c and 3d communicate with a plurality of cylinder holes of the pump case 5. FIG.
As shown in the figure, a pair of holes formed at the time of forming an aluminum casting having a large diameter at the bottom and gradually becoming small is also formed inside the vertical portion of the L-shaped center section 3, and a blind plug is provided below the hole. 4
· Closed by 4 to form vertical holes 3i and 3j. The vertical holes 3i and 3j and the horizontal holes 3g and 3h also intersect and communicate with each other at the intersection of the horizontal portion and the vertical portion of the L-shaped center section 3. On the motor mounting surface 3a,
Kidney ports 3f and 3e, which are also holes for aluminum casting, are formed in communication with the upper portions of the vertical holes 3i and 3j. The kidney ports 3f and 3e communicate with the cylinder holes of the motor case 6.

FIG. 6 shows a vertical hole 3 of the L-shaped center section 3.
FIG. 7 is a front sectional view of the L-shaped center section 3 of the embodiment in which the portion for closing i.3j is closed by high-pressure relief valves 44. In this embodiment, the high-pressure relief valves 44 are provided with a safety valve mechanism for releasing the abnormally high pressure to the axle case, that is, to the tank when an abnormally high pressure is generated in a closed circuit between the hydraulic pump device and the hydraulic motor device. Is composed.

FIG. 8 shows a vertical hole 3i of the L-shaped center section 3.
3j is a side sectional view of a configuration in which the closed portion of 3j is used as charge ports 54 for filling the inside of the closed circuit with hydraulic oil during assembly, and FIG. 9 is a front sectional view of the L-shaped center section 3 similarly. . The lower ends of the charge ports 54 are exposed to the outside from the bottom outer surface of the lower axle case 2, and a threaded blind plug 55 is screwed into the opening. After assembling the axle drive, it is necessary to completely bleed the air in the closed circuit and to spread the hydraulic oil to every corner,
A charge port 54 is provided to open the screw blind plug 55, and the hydraulic oil is forcibly injected from the blind plug 55.

FIG. 10 is a side sectional view of a structure in which the charge ports 3k and 3l are integrally protruded from the L-shaped center section 3, and FIG. 11 is a front sectional view of the same. In this case, the charge ports 3k and 3l are integrally formed with the L-shaped center section 3 and are formed as an aluminum casting, and the lower ends of the charge ports 3k and 3l are exposed from the holes formed in the lower axle case 2 to the lower surface. The screw blind plugs 45 are screwed into the portion. FIG. 12 discloses a hydraulic circuit diagram in which high-pressure relief valves 44 are provided at closed positions of lower ends of the vertical holes 3i and 3j as shown in FIGS.

Motor mounting surface 3 of L-shaped center section 3
a is provided with a hydraulic motor device, and when the motor case 6 of the hydraulic motor device rotates on the motor mounting surface 3a,
Hydraulic pressure generated in the kidney port 3e or the kidney port 3f on the high pressure side of the L-shaped center section 3 acts as a bending stress on the vertical portion where the motor mounting surface 3a is formed. The bending stress is determined by setting the position of the pump mounting surface 3b below the axial center position of the motor shaft 12, particularly the position L1 of the motor shaft 12 and the pump mounting surface 3b, as in the present invention.
If the position L1 is far from the position L1, depending on the material of the L-shaped center section 3, there is a problem that the vertical portion is bent and hydraulic oil leaks from between the motor case 6 and the motor mounting surface 3a. It appears remarkably.

In order to solve the problem that the vertical portion is bent, the L-shaped center section 3 has the following reinforcing structure. That is, in FIG. 13, reinforcing ribs 3m are integrally formed on both sides of the L-shaped center section 3 so as to be in contact with the rear surface of the vertical portion and the horizontal portion. The presence of the reinforcing ribs 3m suppresses the bending of the vertical portion of the L-shaped center section 3. FIG. 14 shows that the L-shaped center section 3 has through holes for fixing bolts 14 and 15 for fixing the L-shaped center section 3 to the mounting surface of the upper axle case 1 on both sides of the vertical portion of the L-shaped center section 3.
The height of the seat 3n is formed so as to substantially coincide with the axial position of the motor shaft 12. With this configuration, the portion of the seat surface 3n also functions as a reinforcing rib. FIG. 15 shows a pump mounting surface 3b in which the seating surfaces 3n 'of the through holes for the fixing bolts 13, 14, 15 are made continuous so that the height thereof substantially coincides with the axial center position of the motor shaft 12. Only the portion has a concave shape and is set below the axis position of the motor shaft 12. Even with this configuration, the bending of the vertical portion of the L-shaped center section 3 can be reinforced.

[0021]

As described above, the present invention has the following advantages. With this configuration, the position of the pump shaft 11 can be relatively lowered with respect to the position of the motor shaft 12 as compared with the conventional axle driving device. As a result, the position of the belt transmission mechanism for inputting the engine power is lowered, and the floor of the vehicle getting on and off can be easily lowered. That is, the position of the pulley fixed to the tip of the pump shaft 11 can be lowered, and the position of the belt transmission mechanism from the engine to the pulley can be lowered, so that the HST transmission integrated with a vehicle with a low floor specification can be integrated. It was possible to construct an axle drive device of the shape. Further, since the position of the height L1 of the joint fixing surface between the upper axle case 1 and the lower axle case 2 matches the axis of the motor shaft 12 and the position of the pump mounting surface 3b is deviated, the pump shaft 11 When the bending force is applied, the force for peeling off the hydraulic pump from the pump mounting surface 3b is not the force for peeling off the joint surface between the upper axle case 1 and the lower axle case 2, and the axle drive The strength of the device can be improved.
Further, the height of the pump mounting surface 3b is adjusted by the upper axle case.
Lower than the height L1 of the joint fixing surface between the first axle case 2 and the lower axle case 2.
Axle case with respect to the pump mounting surface 3b.
The mounting seats 1a, 1b, and 1c that constitute the
Height of the joint fixing surface between the lower axle case 1 and the lower axle case 2
Because it is deflected below L1, the upper axle case
1 and the lower axle case 2 and the axle case
Joining of mounting seats 1a, 1b, 1c and center section 3
Since the fixing surface has been biased, issued the strength against bending force
It was possible to take the configuration to conduct.

The position of the hydraulic pump mounting surface 3b is made coincident with the height L2 of the joint fixing surface of the L-shaped center section 3 to the lower surface of the upper axle case 1, so that the upper axle case 1 and the lower axle are aligned. Since it is arranged so as to be deviated below the horizontal joint surface with the case 2, the position of the hydraulic pump and the pump shaft 11 can be relatively lowered with respect to the entire axle case, and the axle case can be downsized. Can, HS
This makes it possible to reduce the size of the entire axle drive unit integrated with the T transmission. Further, the position of the height L1 of the joint fixing surface between the upper axle case 1 and the lower axle case 2 and the position of the motor shaft 1
2 and the position of the pump mounting surface 3b is deviated, and the position of the L-type center section 3 bonded to the lower surface of the upper axle case 1 and the position of the pump mounting surface 3b match. When a bending force is applied to the pump shaft 11, the center section 3 and the upper axle case 1 are simultaneously moved together with the force for peeling the hydraulic pump from the pump mounting surface 3 b.
Of the L-shaped center section 3 on the lower surface of the upper axle case 1, the height L2 of the joint fixing surface of the L-shaped center section 3 to the lower surface of the upper axle case 1 Since this force is deviated below the height L1, this force does not become a force for peeling the joint surface between the upper axle case 1 and the lower axle case 2 as it is, and the strength of the axle drive device can be improved. You can.

[Brief description of the drawings]

FIG. 1 is a front sectional view of an axle drive device of the present invention.

FIG. 2 is a plan view showing a state where an upper axle case 1 is removed.

FIG. 3 is a side sectional view of a vertical portion of the L-shaped center section 3;

FIG. 4 is a horizontal sectional view of a horizontal portion of the L-shaped center section 3.

FIG. 5 is a front sectional view of a portion of a lateral hole 3g of the L-shaped center section 3;

FIG. 6 is a side sectional view of an embodiment in which portions for closing the vertical holes 3i and 3j of the L-shaped center section 3 are closed by high-pressure relief valves 44;

FIG. 7 is a front sectional view of the L-shaped center section 3;

FIG. 8 is a side sectional view of a configuration in which closed portions of the vertical holes 3i and 3J of the L-shaped center section 3 are used as charge ports 54 at the time of assembly.

FIG. 9 is a front sectional view of the L-shaped center section 3;

FIG. 10 is a side sectional view of a configuration in which the charge ports 3k and 3l are integrally protruded from the L-shaped center section 3.

FIG. 11 is a front sectional view of the same.

FIG. 12 is a hydraulic circuit of the axle drive device of the present invention.

FIG. 13 shows reinforcing ribs 3m · 3 on both sides of the vertical section of the L-shaped center section 3 so as to be in contact with the vertical section.
FIG. 4 is a perspective view of an L-shaped center section 3 integrally formed with m.

FIG. 14: Insertion holes for fixing bolts 14 and 15 are set on both sides of the vertical portion of the L-shaped center section 3, and the seat surface 3n thereof
FIG. 2 is a perspective view of an L-shaped center section 3 formed so that the height of the center section 3 substantially coincides with the axial position of a motor shaft 12.

FIG. 15 shows a portion where the seating surface 3n ′ of the insertion hole for the fixing bolts 13, 14, 15 is continuous, the height of which is substantially equal to the axial position of the motor shaft 12, and the pump mounting surface 3b is formed. FIG. 4 is a perspective view of an L-shaped center section 3 having only a concave shape and set below an axial center position of a motor shaft 12.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Upper axle case 1a, 1b, 1c Mounting seat 2 Lower axle case 3 L-shaped center section 3a Motor mounting surface 3b Pump mounting surface 3c, 3d Kidney port

Claims (2)

(57) [Claims] An axle case is formed by vertically joining an upper axle case and a lower axle case, and an L-shaped center section is fixed inside the axle case. The upper surface of the horizontal portion is a mounting surface 3b of a hydraulic pump constituting the HST transmission, and the outer surface of the vertical portion of the L-shaped center section 3 formed orthogonal to the pump mounting surface 3b is a hydraulic motor of the HST transmission. In the configuration formed on the mounting surface 3a, the height of the joint fixing surface between the upper axle case 1 and the lower axle case 2 is L1, and the motor shaft of the hydraulic motor is attached to the joint fixing surface of the upper axle case 1 and the lower axle case 2. Twelve axis positions are matched,
Adjust the height of the pump mounting surface 3b to the upper axle case 1.
Of the axle case with respect to the pump mounting surface 3b.
The mounting seats 1a, 1b, and 1c constituting the contact fixing surface are
Height L of joint fixing surface between axle case 1 and lower axle case 2
An axle driving device, wherein the axle driving device is deviated below the first position . 2. An axle case is formed by vertically joining an upper axle case 1 and a lower axle case 2, and an L-shaped center section 3 is fixed to the lower surface of the upper axle case 1 inside the axle case. The upper surface of the horizontal portion of the L-shaped center section 3 is used as the mounting surface 3b of the hydraulic pump constituting the HST transmission, and the pump mounting surface 3
b, the outer surface of the vertical portion of the L-shaped center section 3 is mounted on the mounting surface 3a of the hydraulic motor of the HST transmission.
The height of the joint fixing surface between the upper axle case 1 and the lower axle case 2 is L1, and the height of the joint fixing surface of the L-shaped center section 3 to the lower surface of the upper axle case 1 is L2. Upper axle case 1 and lower axle case 2
And the joint fixing surface of the L-shaped center section 3 to the lower surface of the upper axle case 1 is adjusted to the pump mounting surface 3b.
And the height L2 of the joint fixing surface of the L-shaped center section 3 to the lower surface of the upper axle case 1 is larger than the height L1 of the joint fixing surface of the upper axle case 1 and the lower axle case 2. An axle drive device which is deflected downward.