JPH03172631A - Servo-clutch for very small shovel vehicle - Google Patents

Abstract

PURPOSE:To alleviate shocks on the claw clutch by play-fitting a cam plate on the forward-reverse shifting shaft of a multiple disc clutch, and providing the cam plate with an axial and a radial recesses to be pressed with springs via balls for engagement of the clutch. CONSTITUTION:The forward-reverse shift shaft 36 of a very small shovel vehicle is provided with a claw clutch 37 to be engaged with a servo-clutch 39. Ther servo-clutch 39 includes driven clutch plates 42, drive clutch plates 43, both pressed with a first spring 47, and a play-fit cam plate 48. The cam plate 48 is provided with an axial recess 49 on the surface and a radial recess 58 respectively pressed via an axial ball 54 and a radial ball 57 with a second spring 51 and a third spring 56. The servo-clutch 39 alleviates shocks on the claw clutch 37 and protects its from damaged. Ball engagement facilitates initial torque transmission. Clutch slip and disengagement of balls from the recesses prevents damage onto the clutch.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a servo clutch for an ultra-compact excavator, particularly when the claw clutch is engaged or when the resistance on the crawler side becomes large. This invention relates to a servo clutch that reduces the impact that occurs.

[Prior Art] Conventionally, there has been no ultra-compact excavator car that can perform excavation work in narrow spaces. When manufacturing this type of ultra-compact excavator car, it is necessary to downsize the transmission in order to make the vehicle body smaller. In order to drive the left and right crawlers independently and to make pin turns easier, separate forward and backward switching shafts are provided in the transmission case for the left and right, and claw clutches and the like are provided on each of the forward and backward switching shafts. The forward/reverse driving force from the human power shaft is separately transmitted to the left and right forward/reverse switching shafts in a disconnectable manner, and worm gears are interposed between the left and right crawler drive shafts and the forward/reverse switching shafts. A conceivable configuration is to omit the brake mechanism in order to prevent reverse rotation.

[Problems to be Solved by the Invention] The above-mentioned ultra-compact excavator transmits the forward-reverse driving force of the input shaft to the left and right forward-reverse switching shafts using a pawl clutch, etc., but the impact when the pawl clutches are engaged is large. be. In addition, when the engine speed increases rapidly, the driving force is suddenly transmitted to the crawler, which may cause sudden starts or sharp turns, and may overload the pawl clutch, worm gear, etc., which may shorten the life of the parts. It can also have a negative impact.

Therefore, when manufacturing an ultra-compact excavator car, there were technical issues that needed to be solved in order to protect parts such as the transmission pawl clutch, prevent dangers such as sudden starts, and improve operability. The present invention aims to solve this problem.

[Means for Solving the Problems] This invention has been proposed to achieve the above object, and includes a hollow cylindrical clutch bracket with an open end that is pivotally mounted on the forward/reverse switching shaft of the transmission. ,
A multi-disc clutch is formed by alternately stacking driven-side clutch plates slidably connected to the tip and drive-side clutch plates spline-fitted to the forward/reverse switching shaft. A stopper plate is fitted to the rear position of the multi-disc clutch, and a first spring is interposed between the stopper plate and the multi-disc clutch to urge the multi-disc clutch toward the inside of the hollow cylinder of the clutch bracket. Further, a cam plate loosely fitted to the forward/reverse switching shaft is disposed in the hollow cylinder, a recess is formed on the surface of the cam plate, and an insertion hole is formed on the surface of the opposing clutch bracket. A second spring and an axial ball are inserted into the insertion hole, and the axial ball is biased to engage with the recess of the cam plate. A ball hole is drilled in the cam plate, and a third spring and a radial ball are inserted therein, and a plurality of recesses are provided at equal intervals on the circumferential inner surface of the cam plate, and the radial ball is pressed by the third spring. It is an object of the present invention to provide a servo clutch for an ultra-small excavator car, which is formed to engage with the recess.

[Effect 1] When the driving force is transmitted to the forward/reverse switching shaft by the pawl clutch, the driving side clutch plate rotates, and the driving side clutch plate and the driven side clutch plate come into contact while sliding due to the pressure of the first spring. The plate clutch is in a half-clutch state.

At this time, the radial ball inserted into the ball hole of the forward/reverse switching shaft is biased in the radial direction by the pressure of the third spring, and engages with one of the recesses provided on the circumferential inner surface of the cam plate. .

Therefore, the initial rotational force of the forward/reverse switching shaft is transmitted to the cam plate, and together with the friction force generated when the multi-plate clutch is pressed against the cam plate by the first spring, the cam plate is caused to move forward/backward. Attempts to rotate together with the switching axis,
Moreover, the axial pole engaged with the recess on the surface of the cam plate tends to roll and protrude from the recess. However, a second spring is interposed in the insertion hole drilled in the clutch bracket, and the axial ball remains in the recess due to the pressure of this second spring.
Conversely, press the cam plate toward the multi-disc clutch.

Therefore, the multi-disc clutch is compressed by the cam plate and the first spring, and the multi-plate clutch is in complete contact with the servo clutch, and the servo clutch is in full pressure contact, so that the forward/reverse switching shaft and the clutch bracket rotate at the same time.

[Embodiment J] An embodiment of the present invention will be described below with reference to the attached drawings. Figures 1 to 3 show an ultra-compact excavator car, in which a work boom attachment part (2) is provided at the front of the frame (1), and an engine (3) is provided at the rear of the frame (1). ) are listed. A swing bracket (4) is attached to the mounting part (2), and the boom (
The base (5a) of 5) is pivotally mounted. An arm bracket (6) is protruded from the negative side of the swing bracket (4), and the tip of the swing cylinder (7) provided on the negative side of the frame (+) is pivoted to the arm bracket (6). The boom (5) swings left and right due to the telescopic operation of the swing cylinder (7). The boom cylinder (8) installed between the swing bracket (4) and the intermediate portion (5h) of the boom (5) allows the boom (5) to rotate up and down about the base (5-). . One end (9a) of an arm (9) is pivotally attached to the tip (5c) of the boom (5), and is provided between the intermediate part (5b) of the boom and one end (93) of the arm. It is rotated up and down by an arm cylinder (10). Further, a packet (11) is pivotally attached to the tip end (9b) of the arm, and the packet (II) is configured to be rotated by the packet cylinder (1).

A transmission case 0■ is fixedly installed at the bottom of the engine (3), and a drive shaft (+
4) and drive sprockets (1) on each side of it.
'9(+'J) is provided. Passive wheels (10(+(O) are pivotally mounted on the left and right sides of the lower front side of the frame (1), respectively.
Between the drive sprocket (F9 (+ Yu) and the crawler @
(r7) is wrapped.

In addition, the passive wheel (1G
Pivot the seagull and move it downwards using hydraulic cylinder 01.

And the power of the engine (3) is the engine pulley Q1)
The transmission pulley (
c) and rotates the input shaft k) of the transmission. The mission pulley (C) is a two-stage pulley, and a belt (4) is wound around the coaxial pulley (C) to transmit power to the pulley (A) of the hydraulic pump.

Incidentally, reference numeral (A) is an operating lever for the boom (5), packet (11), etc., which is connected to the control valve (1), and 01) is a travel lever for switching forward and backward movement.

The left and right travel levers (11) are separately installed on the left and right walls of the transmission case 0→ via links, and are connected to the shifter described later. It is a gear shift lever.

Next, the internal structure of the transmission will be explained. Fig. 4 is an exploded view for explaining the meshing state of each shaft and gear. )
The front end of the transmission case (1→) protrudes forward and a mission pulley (c) is fitted into it.
A cylindrical sleeve (B) is reversibly fitted to the rear of the input shaft (B), and an auxiliary transmission shaft (G) is pivotally mounted above the input shaft (B) in parallel with the input shaft (B), and the sleeve can be moved forward and backward to the left and right, respectively. Switching axis 00 (1
) is established.

The rotation of the input shaft (to the input shaft) is decelerated by the auxiliary transmission gear (Gl), and is transmitted to the auxiliary transmission shaft (g) before being transmitted to the drive gear (Gl).
2) to the sleeve υ). On the other hand, a forward gear (G3) and a reverse gear (G4) are loosely fitted to the left and right forward/reverse switching shafts (A), facing each other.
) (G4) with a claw clutch (B) in the middle to create a chic (
It is formed so that it can be slid at (to). The drive gear (G2) is always in mesh with the forward gear (G3),
The gear (G5) of the sleeve (sleeve) always meshes with the reverse gear (G4). A servo clutch (B) and a worm gear (G6
) is provided, and the crawler drive shaft is pivotally mounted perpendicular to the forward/reverse switching shaft (1) and is fitted with a worm wheel (G7) to mesh with the worm gear (G6).

Figure 5 shows the main parts of the forward/reverse switching shaft (1), and as mentioned above, the forward gear (G3) and the reverse gear (G4) are attached to the rear of the forward/reverse switching shaft (to). They are facing each other with the clutch G force in between. A worm gear (G6) is pivotally attached to the front of the forward/reverse switching shaft (G), and a hollow cylindrical clutch bracket (G) is screwed to the rear surface with screws (41), so that both are integrated. The forward/reverse switching axis (1) is designed to rotate freely. Incidentally, the worm gear (G6) and the clutch bracket (2) may be formed integrally, and the screw fixing may be omitted. A plurality of driven side clutch plates (42
) (42)... are arranged so as to be slidable in the axial direction, and are stacked alternately with a plurality of drive side clutch plates (43H43)... spline-fitted to the forward/reverse switching shaft (1). A multi-disc clutch (44) is configured. In addition, a stopper plate (45) is fitted to the forward/reverse switching shaft (to), and the multi-plate clutch (
A slide plate (46) is slidably spline-fitted between the stopper plate (44) and the stopper plate (45), and a first spring (47) is interposed between the slide plate (46) and the multi-plate clutch (44) and the stopper plate (45). 44) to provide a gap AI between the slide plate (46) and the stopper plate (45).

On the other hand, a cam plate (4B) that is loosely fitted to the forward/reverse switching shaft (1) is arranged in a hollow cylinder of the clutch bracket (4Φ), and the surface of the cam plate 1- (4B) is placed at a depth with an appropriate gap in the circumferential direction. Recesses (49), (49), etc. named A2 are bored.

Then, on the surface of the clutch bracket (A) facing the cam play (4B), the recess (49049)
Insertion holes (50) (5 (1)...
and insert a second spring (
51) and a disc-shaped plate (52) is inserted therein. Explaining also FIG. 6, an expansion part (53) is provided in the middle part of the insertion hole (50), and the plate (52) is pressed against the clutch bracket by the pressure of the second spring (51). (The axial ball (54) is loosely inserted in the vicinity of the surface of the insertion hole (50). A part of the axial ball (54) is made to protrude onto the surface of the clutch bracket (■) and the cam plate (48) is attached.
It engages with the recess (49).

Furthermore, as shown in FIGS. 5 and 7, a third ball hole (55) is bored in the axial direction on the surface of the forward/reverse switching shaft (1) that the cam plate (4B) comes into contact with. spring(
56) and a radial ball (57), and a plurality (3 in this example) of recesses (58) (58) (5B) are inserted at equal intervals on the circumferential inner surface of the cam plate (411).
) will be established. Thus, the radial ball (57) is urged in the radial direction by the pressure of the third spring (56) and engages with one recess (58) of the cam plate (4fl).

Next, the operation of the servo clutch will be explained. In Fig. 5, the pawl clutch (B) is slid forward or backward by the shifter (G) to engage with the forward gear (G3) or the reverse gear (G4), and the forward driving force or reverse driving force is generated. The power is transmitted to the forward/reverse switching shaft (1). At this time, the drive-side clutch plate (43H43) spline-fitted to the forward/reverse switching shaft (1) rotates, and the first spring (
47) causes the slide plate (46) to move forward (
left side in the figure), and the drive side clutch plate (43H43
)... and the driven side clutch plates (42) (42)... contact each other while sliding, and the multi-plate clutch (44) becomes in a half-clutch state. As mentioned above, the radial ball (57) inserted into the ball hole (55) of the forward/reverse switching shaft (1)
is engaged with the recess (58) on the circumferential inner surface of the cam plate (48) by the pressure of the third spring (56), so the initial rotational force of the forward/reverse switching shaft (G) is applied to the cam plate (48). 48). Therefore, the first spring (
Coupled with the frictional force generated when the multi-plate clutch (44) is pressed against the cam plate (4B) by 47), the cam plate (4B) tries to rotate together with the forward/reverse switching shaft (a). . At this time, the recess (
The axial ball (54) engaged with the recess (49) tries to roll and protrude from the recess (4g). However, if you try to move the axial ball (54) forward,
The plate pressed by the second spring (51) (
52), and since the pressing force of the second spring (51) is set to be stronger than the pressing force of the first spring (47), the axial ball (54) moves further forward. do not.

Since the multi-plate clutch (44) is in a half-clutch state, the clutch bracket also rotates slightly behind the rotation of the cam plate (48), causing the inclination of the recess (49) to change as shown in FIG. The axial ball (54) remains on the surface, and the cam plate (4B) is connected to the multi-plate clutch (44).
) side. Therefore, as shown in FIG. 9, the cam play (411) gradually moves rearward while pressing against the multi-disc clutch (44) against the pressing force of the first spring (47). When the gap Al between the slide plate (4B) and the stopper plate (45) becomes zero, the movement of the cam plate (48) stops, and the multi-plate clutch (44) is completely in contact with the forward/reverse switching shaft. (1) and the clutch bracket (41) rotate at the same time.

Of course, since the depth A2 of the recess (49) is larger than the gap A1, the slide plate (46)
) comes into contact with the stopper plate (45), the axial ball (54) will not come off from the recess (49).

In this way, the worm gear (G6) screwed to the clutch bracket (3) rotates together with the clutch bracket (G), and the rotation is transmitted to the drive shaft H by being decelerated by the worm wheel (G7). That is, the forward/reverse switching axis (1
) is transmitted to the worm gear (G6) via the servo clutch (b), the rotation gradually increases through a half-clutch state and reaches the same rotation. Therefore, the impact when the pawl clutch 0'i5 is engaged and the impact when the engine speed is increasing are absorbed.

Here, when the engine speed is increased or the resistance on the crawler side is large, the rotation of the forward/reverse switching shaft (g) increases, so that the axial ball is removed from the recess (49) of the cam brake (48). (54) is about to protrude rapidly,
The reaction force causes the cam plate (48) to move against the multi-plate clutch (4
4) Move to the side. Therefore, the multi-disc clutch (44) suddenly comes into close contact and the torque transmission to the clutch bracket (4 [phase]) is about to rise rapidly, but the clutch ball (54) tends to protrude from the recess (49). As a result, the play (52) in the insertion hole (50) is pressed forward, thereby instantly reducing the frictional force of the multi-disc clutch (44) and avoiding sudden torque transmission. After that, the axial ball (54) is pushed back toward the cam plate (4B) by the pressure of the second spring (51), and the cam plate (48) moves backward until the gap Al becomes zero. The condition continues and gradually the multi-disc clutch (44)
come into full pressure contact.

Further, the second spring (51) also acts as a torque limiter. For example, when the crawler bites stones or wood, or when it sinks to the top, the drive shaft H is overloaded.
: If f is applied, parts such as the pawl clutch (b) and worm gear (G6) may be damaged if left as is. In such a case, the recess (49) of the cam plate (4g) is
), and as shown in FIG. 9, the axial ball (54) pushes the plate (52) into the expanded portion (53) against the pressing force of the second spring (51). ) to the stepped portion (53b). Therefore, the axial ball (54) is attached to the cam plate (4B).
The cam plate (48) is disengaged from the axial ball (54) and rotates idly. Therefore, the cam plate (48) does not move toward the multi-disc clutch (44), and the multi-disc clutch (44)
becomes half-clutched and slips, causing the forward/reverse switching axis (
1) idles. In this way, in place of a conventional shear pin (a pin that cuts under a constant load), it is possible to prevent damage to the power transmission system due to sudden torque buildup.

Note that this invention can be modified in various ways without departing from the spirit of the invention, and it goes without saying that this invention extends to such modifications.

[Effects of the Invention] As described in detail in the embodiments of the present invention, a servo clutch is provided between the pawl clutch of the forward/reverse switching shaft and the worm gear to delay power transmission. It absorbs the shock when the clutch is engaged and provides a good operating feel. Further, since the cam plate is engaged with the radial ball, the initial rotational force of the forward/reverse switching shaft is easily transmitted to the cam plate, and a reliable servo effect can be obtained. Then, it is possible to prevent sudden starts and sudden turns due to sudden rotation of the engine, and even if an overload occurs on the crawler side, it is possible to prevent the multi-disc clutch from slipping and damaging parts such as the pawl clutch and worm gear.

In this way, when manufacturing an ultra-compact excavator car, the present invention has various effects such as protecting power transmission system parts from damage and improving operability and safety.

[Brief explanation of the drawing]

The figures show one embodiment of the present invention, in which Fig. 1 is a side view of an ultra-compact excavator, Fig. 2 is a partially cutaway plan view of the same, Fig. 3 is a rear view of the same, and Fig. 4 is a transmission. A developed view for explaining the meshing state of each shaft and gear in the case, Fig. 5 is a vertical sectional view of the main part of the forward/reverse switching shaft in a half-clutched state, and Fig. 6
The figure is a cross-sectional view of the main part of the recess in the same state, and Figure 7 is A of Figure 5.
-A line sectional view, Figure 8 is a cross-sectional view of the main part of the recess with the clutch connected, Figure 9 is a longitudinal cross-sectional view of the main part of the forward/reverse switching shaft in the same state, and Figure 10 is the cross-sectional view of the main part of the recess in the state where the clutch is connected. FIG. 3 is a cross-sectional view of a main part of the recess in a loaded state. (1■...Mission case (1)...Forward/forward switching axis (B)...
・Servo clutch (→...Clutch bracket (42)...Driven side clutch plate (43)...
... Drive side clutch plate (44) ... Multi-plate clutch (45) ... Stopper plate (47) ...
...First spring (48) ...Cam plate (49) ...Recess (50) ...Insertion hole. (51)...Second spring (54)...
... Axial pole (55) ... Ball hole (56) ... Third spring (57) ...
... Radial ball (58) ... Concave patent Applicant: Iseki Agricultural Machinery Co., Ltd. Kobe Steel, Ltd.

Claims (1)

[Claims] A hollow cylindrical clutch bracket with an open end is pivotally attached to the forward/reverse switching shaft of the transmission, and a driven side clutch plate slidably connected to the end is spline-fitted to the forward/reverse switching shaft. A multi-disc clutch is formed by alternately stacking the drive-side clutch plates, and a stopper plate is fitted to the rear position of the multi-disc clutch on the forward/reverse switching shaft, and a stopper plate is fitted between the stopper plate and the multi-disc clutch. A first spring is interposed to bias the multi-plate clutch inward of a hollow cylinder of the clutch bracket, and a cam plate loosely fitted to the forward/reverse switching shaft is disposed within the hollow cylinder;
A recess is formed in the surface of the cam plate, and an insertion hole is formed in the surface of the opposing clutch bracket. A second spring and an axial ball are inserted into the insertion hole, and the axial ball is inserted into the recess of the cam plate. At the same time, a ball hole is drilled in the axial direction on the surface of the forward/reverse switching shaft that the cam plate contacts, and a third spring and a radial ball are inserted thereinto. A servo clutch for an ultra-small excavator car, characterized in that a plurality of recesses are provided at equal intervals on the inner surface of the circumference, and a radial ball is formed to engage with the recesses when pressed by the third spring. .