JPH0218737Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a starting speed adjusting device for a vehicle such as a tractor.

[Prior art]

Vehicles, such as tractors, are equipped with a forward/reverse switching device in the drive system in order to handle a variety of different types of work, and this is also hydraulically operated using a hydraulic clutch, allowing the forward/reverse switching valve to switch. There are some that are designed to control it. The hydraulic type does not require switching of the main clutch and has the advantage of being easy to operate.

[Problem that the invention attempts to solve]

This type uses a combination of a pressure regulating valve and an orifice valve in the forward/reverse switching valve so that the starting speed can be adjusted by changing the pressure increase characteristics on the hydraulic clutch side when switching the forward/reverse switching valve. has been done. However, in the past, due to space constraints, the forward/reverse switching valve was attached to a shielding plate or the like inside the instrument panel, making it impossible to easily adjust the orifice valve.

[Means for solving problems]

The purpose of this invention is to overcome these conventional problems and to make it possible to easily adjust the adjustment shaft of the orifice valve from outside the instrument panel, and its features are as follows: A forward/reverse switching valve that controls the forward/reverse switching device of the running system is provided inside the instrument panel, and an orifice valve is installed in the forward/reverse switching valve to adjust the starting speed by changing the pressure increase characteristic when the switching valve is switched. In the vehicle equipped with the orifice valve, the adjustment shaft of the orifice valve is extended to the vicinity of the side wall of the instrument panel, and an adjustment hole is provided in the side wall opposite to this adjustment shaft.

[Effect of idea]

According to the present invention, the adjustment shaft is extended to the vicinity of the side wall of the instrument panel, and the adjustment hole is provided in the side wall opposite to this, so that even if the forward/reverse switching valve is inside the instrument panel, Regardless, there is an advantage in that the starting speed can be changed by easily operating the adjustment shaft from the outside.

[Embodiment] Hereinafter, the present invention will be described in detail with reference to the illustrated embodiment. In FIG. 2, reference numeral 1 denotes a tractor body, which is composed of an engine 2, a flywheel housing 3, a transmission case 4, and the like. 5 is the first part,
6 is a bonnet that covers the engine 2, and includes a pair of fixed covers 7 on both sides of the upper part;
It is comprised of an upper cover 8 provided in between so as to be freely openable and closable, a side cover 9 removably provided below a pair of fixed covers 7, and a front cover 10. Reference numeral 11 denotes an instrument panel, which is provided at the rear of the bonnet 6. The instrument panel 11 is provided with various instruments, and is also provided with a fuel tank 12 inside. A shielding plate 13 is fixed on the tractor body 1 so as to partition the bonnet 6 and the instrument panel 11 at the rear of the engine 2.
Some of them are installed. 14 is the handle,
It is supported by a handle post 15, and the handle post 15 is attached to a steering box 16 on the tractor body 1. A pitman arm 17 for interlocking the handle 14 and the above-mentioned gear 5 is supported on the steering box 16 by a sector shaft 18. Reference numeral 19 denotes a forward/reverse switching valve for controlling a hydraulic clutch type forward/reverse switching device 20 built into the traveling system within the transmission case 4. It is attached to the rear side of the plate 13 with bolts. The switching valve 19 has a switching lever 22, which can be operated by a forward/reverse switching lever 26 on the handle post 15 side via a rod 23, a ring 24, and a rotation shaft 25. The rotating shaft 25 is supported by a bracket on the handle post 15, and a switching lever 26 and a link 24 are fixed to the upper end and lower end of the rotating shaft 25, respectively.

The switching valve 19 is incorporated into a valve body 29 together with a pressure regulating valve 27 and an orifice valve 28, as shown in FIG. The switching valve 19 has a spool 30 rotatably inserted into the valve body 27, and by rotating the spool 30, it selectively connects the pump port 31, drain port 32, forward clutch port 33, and reverse clutch port, respectively. . Spool 30
One end projects outwardly through a cover 34 attached to the valve body 29, and the switching lever 22 is provided at the projecting end. The switching lever 22 can be positioned at neutral, forward, and reverse positions by a positioning mechanism. The pressure regulating valve 27 includes a valve body 35 that is disposed so as to be slidable in the axial direction facing the spool 30 of the switching valve 19, and a valve body 35 that is slidably disposed in the axial direction on the side opposite to the spool 30 with respect to the valve body 35. A piston 36 is arranged, two large and small springs 37 and 38 are interposed between the valve body 35 and the piston 36 and are concentric with each other, and a rod that regulates the distance between the valve body 35 and the piston 36. It is equipped with 39. The valve body 35 is provided to open and close the drain port 40. The sliding range of the piston 36 is restricted by a stepped portion 41, and among the two large and small springs 37, 38,
The outer spring 38 is longer than the inner spring 37. The orifice valve 28 is interposed in the middle of oil passages 43 and 44 formed in the valve body 29 and a cover 42 detachably attached to the valve body 29 to communicate the pump port 31 side of the switching valve 19 and the back of the piston 36. has been done. The orifice valve 28 is the third
As shown in the figure, orifice holes 4 with different diameters are installed in a disc-shaped valve body 49 fixed to the inner end of the rotating shaft 45.
A plurality of 6, 47, 48 are formed in the circumferential direction,
The rotation shaft 45 rotatably penetrates the cover 42 and projects outward. An adjustment shaft 50 is provided on the same axis at the outer end of the rotation shaft 45 via a joint member 49, and the joint member 49 is provided with a shaft for positioning each orifice hole 46, 47, 48 at a position corresponding to the oil passage. A positioning mechanism 51 is incorporated. The adjustment shaft 50 extends straight to the vicinity of the side wall 52 of the instrument panel 11, and has a driver 53 at its tip.
Alternatively, an engagement groove 54 into which a coin or the like can be engaged is formed. On the other hand, an adjustment hole 55 is provided in the side wall portion 52 in correspondence with the adjustment shaft 50, and a driver 53 or the like can be inserted through the adjustment hole 55. Note that the adjustment hole 55 is normally closed with a removable cap 56 made of rubber or the like.

Next, the effect will be explained. When switching forward or backward, the switching valve 19 is activated by the switching lever 26 near the handle 14.
operate. Now, if the switching valve 19 is switched to the forward side, the oil in the pump port 31 is supplied to the reverse clutch port 33 side, and the valve body 35 of the pressure regulating valve 27 is moved against the spring 37 to the left in FIG. direction and flows to the drain port 32. On the other hand, oil flows from the oil passage 32 to the piston 36 through the oil passage 43, with the flow rate being appropriately restricted by the orifice valve 28.
1, the piston 36 slides to the right in FIG. 1 until it comes into contact with the stepped portion 41.
During this time, the piston 36 compresses the spring 37, and then
Further, since both springs 37 and 38 are compressed, the circuit pressure of the reverse clutch port 33 increases with a boost characteristic in which the slope becomes large midway. When the piston 36 comes into contact with the stepped portion 41, the valve body 35 is held in contact with the rod 39.

With such an operation, the forward clutch is connected and the vehicle starts moving, but in such a case, the orifice valve 28
The starting speed can be adjusted by arbitrarily selecting the diameters of the orifice holes 46, 47, and 48.
For example, if the orifice hole 46 is set to the maximum, the flow rate is large, so the rise in pressure characteristics is good, and a sudden start is possible.

During this adjustment, remove the cap 56 of the adjustment hole 55, insert a screwdriver 53 or the like from the outside, and turn the adjustment shaft 50.
rotates and therefore can be easily adjusted even though it is located inside the instrument panel 11. Further, since there is an adjustment hole 55 in the side wall portion 52 of the instrument panel 11, in the case of a small tractor, etc., adjustment can be made from the driver's seat at the rear with a slight extension of the hand.

A hydraulic pump 57 that supplies pressure oil to the forward/reverse switching device 20 and others is fixed to the fuel pump casing 59 of the engine 2 with bolts 60 via a gear case 58 and the like, as shown in FIG. 61 to gears 62, 63, pump shaft 6
It is designed to drive 4. fuel camshaft 61
is supported via a bearing 65, and this fuel camshaft 6
A gear 62 is fixed to 1. The gear 63 integrally has a cylindrical boss portion 66.
It is supported in a cantilevered manner by a bearing 67 via. A pump shaft 6 is provided inside this boss portion 66.
4 are internally fitted and connected via a spline portion 68. The engaging portions of the gears 62 and 63 can be sufficiently lubricated by scraping up the lubricating oil at the inner bottom of the gear case 58, but it is difficult to lubricate the spline portion 68 because it is internal.

Therefore, a protrusion 69 protruding into the inside of the gear 63
is provided on the side wall of the gear case 58 to guide the lubricating oil flowing down the inner surface of the side wall to the inner circumferential side of the gear 63. On the other hand, an axial groove 70 communicating with the spline portion 68 is provided on the inner circumference of the gear 63. If a plurality of spline portions are formed in the direction, the spline portion 68
can be sufficiently lubricated. Note that 71 is a ring with groove 7.
It is fitted onto the inner periphery of the gear 63 so as to close the end of the gear 63.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is a sectional view of the main parts, FIG. 2 is a cutaway side view of the front part of the tractor,
FIG. 3 is a perspective view of the orifice valve, and FIG. 4 is a sectional view of the pump drive section. 1... Tractor body, 2... Engine, 6...
Bonnet, 11... Instrument panel, 14... Handle, 19... Forward/forward switching valve, 20... Forward/forward switching device, 27... Pressure regulation valve, 28... Orifice valve, 50... Adjustment shaft, 55... ...adjustment hole.

Claims (1)

[Scope of utility model registration request] A forward/reverse switching valve that controls the forward/reverse switching device of the running system is provided inside the instrument panel, and an orifice valve is installed in the forward/reverse switching valve to adjust the starting speed by changing the pressure increase characteristic when the switching valve is switched. A vehicle starting speed adjustment characterized in that the adjustment shaft of the orifice valve is extended to the vicinity of the side wall of the instrument panel, and an adjustment hole is provided in the side wall opposite to the adjustment shaft. Device.