JP2932737B2 - Swash plate type compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called swash plate type compressor suitable for use as, for example, a refrigerant compressor for a vehicle air conditioner.

[0002]

2. Description of the Related Art In a swash plate type compressor, a swash plate is attached to a shaft which is rotationally driven by an external power, and the swash plate swings with the rotation when the shaft rotates. As a result, a component of the oscillating motion is taken out and one or several pistons are reciprocated in a cylinder, and a fluid such as a refrigerant is expanded and contracted by expanding and contracting the volume of a working chamber formed by the cylinder and the piston. Inhalation,
It is designed to be compressed. In order to transmit the rocking movement of the swash plate to the piston, the piston, for being received input a peripheral portion of the swash plate of the rocking motion is inclined, and a groove having a width sufficient provided, A pair of hemispherical shoes that can rotate freely in a hemispherical recess provided at the position where the center line of the piston in the groove passes, sandwiching the peripheral edge of the swash plate this shoe, by sliding against the swash plate which rotates while only component of the rocking motion of the swash plate is transmitted to the piston, Ru it is reciprocated, times <br/> rolling movement Is not transmitted to the piston.

[0003] In this case, when the shaft is rotated the swash plate by being driven via an electromagnetic clutch or the like, the piston without rotational movement, it is necessary to only reciprocate in the cylinder being inserted Therefore, as described above, the rotational motion of the swash plate is prevented from being transmitted to the piston by slidably engaging the shoe provided in the groove of the piston with the swash plate. By performing the motion, at least a rotating force is generated on the piston slidingly engaged with the swash plate via the shoe.In the conventional swash plate compressor, the outer peripheral surface of the peripheral edge of the swash plate is attached to the piston. The rotation of the piston is prevented by contacting the bottom surface of the groove provided.

[0004]

[Problems that the Invention is to Solve In a conventional swash plate type compressor, because mechanisms to suppress the rotation of the piston were those as described above, by the rotation force that acting on the piston, which accepted the swash plate Since the bottom of the groove of the piston slides after colliding with the outer peripheral surface of the peripheral edge of the swash plate, friction and wear are generated on those surfaces, not only reducing the durability of the piston and the swash plate, but also There is a possibility that abnormal noise may be generated to give uncomfortable feelings or anxiety to the occupants of the automobile. In order to solve these problems in the prior art, the present invention counteracts or reduces the moment of the rotation force acting on the piston of the swash plate type compressor, thereby reducing the wear caused by the direct contact between the piston and the swash plate. It is an object of the present invention to prevent and improve the durability thereof and at the same time prevent the generation of abnormal noise.

[0005]

In order to solve the above-mentioned problems, the present invention provides a housing assembly, a cylinder formed inside the housing assembly, and a slidably and airtightly mounted cylinder. A piston that forms a working chamber whose volume expands and contracts in the cylinder, a shaft supported inside the housing assembly, and a rocking motion that is integrated with the shaft and driven to rotate. A rotating swash plate, and a shoe rotatably supported between the swash plate and the piston to transmit a reciprocating motion component of the swinging motion of the swash plate to the piston. , R: distance between the center and the center of the shaft the piston r: radius of the shoe [delta]: offset K of the shoe relative to the center of the piston, K ': If it is a constant Then, the center of the shoe with respect to the center axis of the piston, in a direction approaching the shaft, δ = [R− ｛R ² −8 (K / K ′) · r ² ｝ ^1/2 ] / 2 . And a swash plate type compressor characterized by being provided with offset.

[0006]

The swash plate type compressor according to the present invention includes a shoe rotatably supported between the swash plate and the piston in order to transmit a reciprocating motion component of the swinging motion of the swash plate to the piston. together are the center of the shoe relative to the piston central axis, in a direction toward the shaft, [delta] = ^{[R- {R 2 -8 (K /} K ') · r 2} 1/2 ] / 2's since kicking set is offset, even if the rotating moment in the same direction as that the shoe is generated by the rotation of the swash plate, therewith the shoe simultaneously revolution moment of magnitude commensurate with the offset amount around the center axis of the piston There as they may eggplant originating in a direction opposite to the rotating direction of the swash plate, the rotating moment is transmitted from the shoe to the piston is canceled
Thus , wear and abnormal noise due to direct contact between the piston and the swash plate due to rotation of the piston are prevented.

[0007]

DETAILED DESCRIPTION FIG. 1 shows an overall structure of a swash plate type compressor 100 as a real施例of the present invention, the housing 10 of the compressor 100, the front is fastened integrally by through bolts (not shown) It comprises a housing 12, a rear housing 14, and front and rear portions of a front head 16 and a rear head 18 before and after them. An abutment surface of each adjacent portion is sealed by providing an O-ring or the like as shown. A front side plate 20 is sandwiched and fixed between the front housing 12 and the front head 16, and a rear side plate 22 is sandwiched and fixed between the rear housing 14 and the rear head 18.

[0008] Front housing 12 and rear housing
In the corresponding positions of the fourteen cylinders 24 each
And 26 are provided to be open, and each of them
The pistons 28 on both sides are inserted one by one for each pair.
When driven before and after them, they expand and contract to change the volume.
Working chamber 30 (only the rear side is shown)You
You. Inside the front head 16 and the rear head 18,
Each suction chamber 32,34 and discharge chamber 36,38 formed
And they are connected via a suction valve 40 and a discharge valve 42.
Each cylinder 24,To the working chamber 30 in 26
(In the figure, only some of them
Is shown. ). The discharge valve 42 has a valve retainer 44.
Is attached.

[0009] Shaft 46 is a radial bearing 4 through the center of the integrated wafer maggots <br/> ring of the swash plate type compressor 100
8 and 50, and are sealed by a sealing device 52 and the like. In a swash plate chamber 54 formed between the front housing 12 and the rear housing 14, a swash plate 56 is fixed to the shaft 46, and thrust bearings 58 and 60 are provided before and after the swash plate 58 between the housings 12 and 14. And supports the swash plate 56 in the axial direction. Periphery of the swash plate 56, all of the pistons 2
8 are simultaneously inserted into the groove 62 formed. In a position offset by a predetermined amount δ in a direction rather closer to the shaft 46 than the center of the piston 28, on both side surfaces of each groove 62 is provided opposite a recess 64 of hemispherical, hemispherical inserted in their recesses shape of the shoe 66 is slidably engaged across the front and rear surfaces of the peripheral portion of the swash plate 56.

The basic operation of the swash plate type compressor 100 as a compressor is the same as that of the conventional one, and the suction chamber 32 ,
The coolant 34 is supplied with a low-pressure, low-temperature refrigerant from an evaporator of an air conditioner, for example, through the suction side passage 68 and the swash plate chamber 54.
When an electromagnetic clutch (not shown) is connected, the shaft 46 is rotationally driven from the engine of the automobile or the like.
Reciprocates in the cylinders 24 and 26, but when the working chamber 30 expands, the suction valve 40 opens and the suction chamber 3
2, 34 refrigerant is sucked into working chamber 30, then when the working chamber 30 is reduced, the discharge valve 42 is opened with the suction valve 40 is closed, the high pressure compressed in working chamber 30, high-temperature refrigerant To the discharge chambers 36 and 38. Discharge chamber 36 ,
Reference numeral 38 is connected through a discharge-side passage 70 to, for example, a condenser of an air conditioner. (However, in FIG. 1, the suction side passage 6
8 and the discharge side passage 70 show only one of the left and right sides, respectively. )

In this case, as shown in FIG. 2A and an enlarged view of a main part thereof, the center of the shaft 46 on the outer peripheral edge of one shoe 66 which is in sliding contact with the swash plate 56. A point A where the distance from the line is the maximum value R ₁ and a minimum value R
Circumferential speed V ₁ of the swash plate 56 in ₂ to become a point B, V ₂ is, R ₁ is the rotational radius from the center line of the shaft 46, respectively
And the magnitude is proportional to R ₂ , and if the angular velocity of the shaft 46 is ω, then V ₁ = R ₁ ω V ₂ = R ₂ ω, and since R ₁ > R ₂ , V ₁ > a V _2.

In this case, the target swash plate type compressor is of the type in which the shoe 66 is supported on the piston 28 which does not revolve.
8 if they cannot rotate on points A and B
The relative sliding speed between the swash plate 56 and the shoe 66 becomes equal to the peripheral speeds V ₁ and V _{2. Due} to the relationship V ₁ > V ₂ , the relative sliding speed on the shoe 66 is Although a state in which the sliding speed is different occurs, the shoe 66 is also rotatably supported on the piston 28 in the related art, so that one shoe is balanced by the partial frictional force balance on the sliding surface. Since the relative sliding speed of the swash plate 56 at the point A and the point B on the point 66 tends to become the same value, the shoe 66 has a peripheral speed corresponding to the difference between the peripheral speeds V ₁ and V _2. It will rotate in the same direction as the swash plate 56.

Assuming that the rotation moment (rotation force) is m, the rotation moment m extends not only to the shoe 66 but also to the piston 28, so that the piston 28 and the shoe 66 are coaxial as in a conventional swash plate type compressor. In a relationship (see Figure 2)
At this time, since there is no other moment opposing the rotation moment m of the shoe 66, the moment m acts on the piston 28 as it is to rotate the piston 28 in the same direction as the shaft 46 as shown in FIG. As a result, the bottom surface of the groove 62 of the piston 28 collides with the outer peripheral surface 72 of the peripheral edge of the swash plate 56, and further rotation of the piston 28 is prevented. Abnormal noise or wear on these surfaces due to contact with these surfaces other than the friction described above is as described above as the prior art and its problems.

Therefore , in an embodiment of the present invention , FIG.
As shown in the (a), about the direction rather closer to the shaft 46 of the shoe 66, by offsetting by a predetermined value δ from the center line of the piston 28 (shifting) direction canceling the rotating moment m Is generated. In other words, when the shoe 66 is eccentric with respect to the piston 28 as shown in the drawing, the swash plate 56 rotates, so that the shoe 66 is rotated around the center of the piston 28 in addition to the rotation moment m. A moment m 'for revolving in the direction opposite to the shaft 46 is generated. Between these moments m and m ′, the moment for rotating the piston 28 is M
Then, if the offset amount δ is appropriate, the rotation moment m of the shoe 66 and the revolution moment m ′ are balanced, so that the rotation moment M of the piston 28 disappears. Will do. FIG. 5 shows the relationship between the offset amount δ and the rotational moment M of the piston 28 as a diagram. Thus, public rolling moment m 'is commensurate with the rotating moment m, the piston 2
It makes the chromophore at the distal end Mento M value substantially zero to try to rotate the 8
By finding the optimal value of the offset amount δ
The problem of abnormal noise and wear due to collision between the bottom surface of the groove 62 of the piston 28 and the outer peripheral surface 72 of the swash plate 56 is eliminated.

Although it is difficult to accurately calculate the magnitude of the rotation moment m of the shoe 66, the magnitude is proportional to the difference between the peripheral speeds V ₁ and V ₂ as described above. Next, a method for calculating the optimum value will be described. As shown in FIGS. 2 and 4, each symbol is defined as follows. R: distance between the center of the shaft 46 and the center of the piston 28 r: radius of the shoe 66 δ: offset amount of the shoe 66 ω: rotational angular velocity of the swash plate 56 R ₁ : maximum value of the distance between the center of the shaft 46 and the shoe 66 _{That, R 1 = R + r-} δ R 2: the minimum value of the distance between the center and the shoe 66 of the shaft 46 _{i.e., R 2 = R- (r +} δ) V 1: circumferential speed of the swash plate 56 at the point a i.e., V ₁ = R ₁ ω V ₂ : peripheral speed of the swash plate 56 at the point B, that is, V ₂ = R ₂ ω

As is apparent from the above description, the shoe 6
6, the magnitude of the rotation moment m is the difference between the peripheral speeds V ₁ and V
₂ and the amount of offset δ . Rotational moment m without offset as in the past
Shoe 6, a number proportional constant as _{K, m = K (V 1} -V 2) · r = K · 2rω · r also caused by the offset according to the present invention
6 orbital moment m 'around the central axis of the piston 28
It is a proportionality constant 'a, m' K Again = K 'conditions rotating moment M of the (R-δ) ω · δ piston 28 is canceled out, M = m-m' from a = 0, [delta] ² - Rδ + (K / K ′) · 2r ² = 0 By solving the above equation with respect to δ, δ = [R ± ｛(R ² −8 (K / K ′) r ^{2 1/2} ] / 2] Since the amount δ is considered as a very small amount, δ =
[R− ｛R ² −8 (K / K ′) · r ² ｝ ^1/2 ] / 2. From the above equation, the piston 2
By substituting the distance R to the center of 8 and the radius r of the shoe 66 (all are constants), the optimum value of the offset amount δ can be obtained. Incidentally, the proportional constants K is a value determined by the material and the lubricating conditions such as shaft 46, which can be determined by experiment.

[0017]

According to the present invention, the offset amount of the shoe is provided.
Is calculated, so that the rotation mode acting on the shoe
The results can be canceled instrument completely rotation of the piston Ru is reliably prevented in the swash plate type compressor. Follow
Te, since no arresting <br/> rotation of the piston by direct contact with the swash plate, there is no possibility of wear due to direct contact with both the durability of the piston and the swash plate is increased, abnormal noise due to direct contact Is prevented from occurring. In particular, according to the present invention, the calculating the center of the shoe to the closer Keru direction to the shaft
Since the optimum value only will offsets, can be made smaller than the conventional outside diameter of the swash plate, the swash plate, thus the entire compressor can be a light weight compact.

[Brief description of the drawings]

1 is a longitudinal sectional front view showing a swash plate type compressor as a real施例of the present invention.

FIGS. 2A and 2B are conceptual diagrams showing operating states of a swash plate, a shoe, and a piston in a conventional example, where FIG.
(B) is a principal part enlarged view of (a).

FIG. 3 is a perspective view showing rotation of a piston by rotation of a swash plate in a conventional example.

[4] A conceptual diagram for explaining the effect of the offset of the shoe relative to the piston in actual施例of the present invention, (a) is a by embodiments of the present invention, (b) is for comparison Shows a conventional example.

FIG. 5 is a diagram showing a relationship between a shoe offset amount and a rotation force acting on a piston.

[Explanation of symbols]

10 : Housing 28 : Piston 46: Shaft 56: Swash plate 66 : Shoe 100 : Swash plate compressor

Continuation of the front page (56) References JP-A 56-132380 (JP, U) JP-A 63-93480 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F04B 27 / 08

Claims (1)

(57) [Claims] 1. A housing assembly, a cylinder formed inside the housing assembly, and a piston slidably and airtightly inserted into the cylinder to form a working chamber whose capacity is expanded and contracted in the cylinder. A shaft supported inside the housing assembly, a swash plate integrated with the shaft and driven to rotate with a rocking motion, and a reciprocating motion of the rocking motion of the swash plate. together and a said are swash plate and is rotatably supports between the piston shoe to convey ingredients into the piston, R: distance between the center and the center of the shaft the piston r: the the radius of the shoe [delta]: offset K of the shoe relative to the center of the piston, K ': when a constant, the center of the shoe with respect to the central axis of said piston, said pusher Toward the bets, [delta] = ^{[R- {R 2 -8 (K /} K ') · r 2} 1/2 ] / 2 but only swash plate type compressor, characterized in that provided by offset.